Previous Brainteaser Results

ERJ Brainteasers and Brainiac of the Month results:

DECEMBER 2016

There was tough competition all round in the final month of 2016, and after extremely lengthy deliberations by our judging panel, our ERJ Brainiac of the Month award has gone to joint winners:

Yuichi “Joe” Sano of Sumiden Steel Wire (Thailand) Co., Ltd in Thailand; and Thierry Montcalm at Soucy Caoutchouc, Canada

Question 4: Anna’s event

For the best employee awards at her rubber company, events manager Anna is making tablecloths for circular tables 6 feet in diameter. The finished tablecloths need to hang down 5 inches over the edge of each table all the way around. To finish the edge of the tablecloths, Anna will fold under and sew down 1 inch of the material all around the edge. For each table, she is going to use a single piece of rectangular fabric that is 120 inches wide. What is the shortest length of fabric in inches, she could use to make a tablecloth without putting any separate pieces of fabric together.

Answer: The correct answer is 84 inches. Well done to John Bowen, consultant, Bromsgrove, Worcestershire, UK; David Mann, manager rubber technology, SI Group, Béthune Cedex, France; Satyadip Saikia, no details given; David Mann, Yuichi “Joe” Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; and Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada., Stephan Cortel, Mesnac,.USA.

Question 3: All at sea

From his luxury yacht, skipper Ian measures the angle of elevation of the top of a lighthouse as 18 degrees. He sails 600 metres directly towards the lighthouse and then measures the elevation of the top of the cliff as 50 degrees. What is the distance from the second position of the yacht to the top of the lighthouse and what is the height of the lighthouse?

Answer: Not such plain sailing for our readers this week, but the answers (rounded up) were: height, 268m and distance 350m. Well done to John Bowen, consultant, Bromsgrove, Worcestershire, UK; Yuichi "Joe" Sano,Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn,Amphur Pluakdaeng, Rayong Province, Thailand; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; and Stephan Cortel, Mesnac,.USA..

Question 2 - Six pack

If 6 plus 6 equals 14, what does 6 multiplied by 6 equal?

Answer: Well done to these select few readers who worked out that the figures were to the base 8, so that 6 x 6 = 44: David Mann, manager rubber technology, SI Group, Béthune Cedex, France; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK;  Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; and John D Burrows, consultant, France; Duncan Thomson, general manager, Wuxi Elbe Polymer Technology Ltd, China.

Question 1: Factory fire

Janice, the fire officer at a rubber factory, notices a blaze in the extrusion area of the plant. From her list of all 142 employees at work that day, she phones two, alerts them, asks them to phone two more people before getting out of the factory. Luckily, everyone answered the phone immediately and got out safely - even though each phonecall took 30 seconds, and it took each employee 90 seconds to get out of the building. How long did it take to evacuate all 142 workers from the factory?

Answer: This was a tough one and generated answers ranging from between 3-8 minutes. However, the official answer is that its took nine rounds of phone calls to alert all 142 employees, which equated to 4 minutes 30 seconds, plus 90 seconds, ie 6 minutes, to fully evacuate the building. Extra well done to Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; and Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada.

NOVEMBER 2016

This month’s award goes to David Mann, manager rubber technology, SI Group, Béthune Cedex, France; who has been an excellent contributor to our brainteasers. Well done to our new ERJ Brainiac of the Month.

Question 4: Domenic's Dilemma

Domenic does not know much about football but he is having a go at predicting the results of 7 matches in the English league next Sunday. What is the probability of him guessing the result (home win, away win or a draw) of every match correctly?

Answer:  Assuming that each match outcome has an equal probability, then for each of the 7 matches the chance of guessing the correct outcome is 1/3. Therefore, for 7 matches the answer is (1/3)^7 = 1/2187 or 0.05%. Well done to John D Burrows, consultant, France; John Bowen, consultant, Bromsgrove, Worcestershire, UK; David Mann, manager rubber technology, SI Group, Béthune Cedex, France; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; Yuichi “Joe” Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong, Thailand Amparo Botella, Ismael Quesada SA, Spain; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Maria Eugenia Aricha, BU Manager – plastic, composite & rubber, EMSA TechnologiaQuimica, Spain; Pete McNeil, Rubber & Plastics News, US.

Question 3: Ashwin’s art

A visit to the Tate Modern art gallery in London, has given Ashwin a new-concept idea for decorating the office. Next day, he brings in hundreds of small, individually numbered prints. With puzzled colleagues watching on, he takes out print no. 30 at 11 o’clock and hangs it on the wall. He repeats the exercise with print no. 240 at 4 o’clock, followed by print no. 315 at 7.30. Which number print will Ashwin hang up at 9.30?

Answer:  Yes the key was angles on the clockface, so at 9:30 he would hang no. 255.Well done to John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; John Bowen, consultant, Bromsgrove, Worcestershire, UK; David Mann, manager rubber technology, SI Group, Béthune Cedex, France;; Yuichi "Joe" Sano Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand;

Question 2:  T Time

A car fitted with ultra-high-performance tires travels from A to B, at a speed of 90km per hour. It takes it time ‘T’ to complete the journey.  A similar car, fitted with budget tires, travels from A to B at a speed of 70km per hour. This time, the journey takes ‘T+ 1 hour’.

How long did it take for the UHP tire-fitted car to complete its journey?’

Answer: Be warned: Our question-setter is threatening revenge after seeing replies to this question fly in almost as soon as Monday’s newsletter went out. The correct answer, 3.5h, reached us in the following order from: François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, France; David Mann, manager rubber technology, SI Group, Béthune Cedex, France; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; John Bowen, consultant, Bromsgrove, UK; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Ronald Meyns, strategic account manager, Goodyear EMEA, Rockwell Automation, Hamburg, Germany; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong, Thailand; John D Burrows, consultant, France; Amparo Botella, Ismael Quesada SA, Spain.

Question 1: Bouncing Tire

A tire is dropped and bounces up to a height that is 75% of the height from which it was dropped. It then bounces again to a height that is 75% of the previous height and so on. How many bounces does it make before it bounces up to less than 25% of the original height from which it was dropped?

Answer: Quite a few readers worked this out at 4, but the correct answer is that on the 5th bounce it bounces up to 23,7%, which is less than 25% of the original height from which it was dropped. Well done to: David Mann, manager rubber technology, SI Group, Béthune, France;; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, France; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; John D Burrows, consultant, France; Ian. P. Jones, managing director, Continental Division, Contitech Power Transmission Group, ContiTech UK Ltd, Wigan, UK; Stephan N Cortel, Mesnac, USA; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; Hans Derwig, managing director Dunlop Service, Drachten, The Netherlands; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy.

OCTOBER 2016

This month's award goes to one of our most consistent performers, who came in well ahead of the pack with the correct answer for question 4. Well done to Marzio Bussola of Parker Hannifin in Italy, our new Brainiac of the Month

Question 4: Meeting Point

A service centre in Paris has sent a replacement machine part by courier to reach a factory near Cologne in seven hours. At precisely the same time, the factory sent a courier with the old part, which needed to be refurbished, to Paris to reach the service centre in nine hours. If the distance was exactly 250 miles, how long was it before the couriers passed each other?

Answer: Ask a simple question and you get hundreds of different answers. Luckily that is not the case with this teaser as most of our readers came up the right answer, 3h 56 minutes 15 seconds, some adding the distances travelled by the two couriers before their paths met. Well done, in order of receipt, to: Marzio Bussola,  Parker Hannifin Manufacturing S.r.l., Italy; François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, France; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; John D Burrows, consultant, France; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; Ian. P. Jones, managing director, Continental Division, Contitech Power Transmission Group, ContiTech UK Ltd, Wigan, UK; Stephan N Cortel, Mesnac, USA; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Rayong Province, Thailand; Hugo Ernesto Vera, Adscripto Proyectos Expansión, FATE S.A.I.C.I., Buenos Aires, Argentina; Tony Neill, National Tyres and Autocare, UK; John Bowen, consultant, Bromsgrove, Worcestershire, UK.

Question 3: Warehouse wonder

There are ‘n’ tires in a warehouse. Six of the tires are ultra-high performance tires. The rest are high performance. A worker takes a tire from the storage hall and fits it on a car. He then then takes at random another tire and fits on another car.  The probability that the worker has picked two UHP tires is 1/3. How many tires are there in the warehouse?

Answer: Good response to this teaser, and most correctly worked out the correct answer, 10: Well done to David Mann, manager rubber technology, SI Group, Béthune, France; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Thailand;  John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; John D Burrows, consultant, France; Thiery Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, France. Stephen Fulton, R&D technology development manager,, Umicore Specialty Materials Brugge NV, Brugge, Belgium; Maria Eugenia Aricha, Emsa Technologia Quimca, Barcelona, Spain.

Question 2: Bigger band

Four-member rock group the Kings of Oblivion has taken on a number of new recruits and transformed into a brass band. The reformed band’s first gig is at a football match, where it is to march onto the pitch in the formation of a solid equilateral triangle. The band members will then rearrange themselves to form a solid square. What is the minimum number of new recruits needed to do this?

Answer: The total number of band members needed is 36 – (triangle of 8 per side, square of 6 per side) so the number of new recruits is 32. Well done to David Mann, manager rubber technology, SI Group, Béthune, France;  John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; John Bowen, consultant, Bromsgrove, UK; John D Burrows, consultant, France; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, Francce. Aditya Biswas, automobile researcher, Segment Y, Goa, India.

Question 1: Tricky taps

At a US rubber chemicals plant, there are two taps on a reactor. One releases hot water, the other cold water, into the vessel, but at varying pressures. If the hot water is 105°F and the cold water is 45°F, and operators can rotate the tap at most 360 degrees, how much would they have to rotate the cold water tap to get the temperature to be 98.6°F, if the hot water is turned on all the way, and could not be turned down?

Answer: This question had too many twists for many, with only a handful of elite answerers accurately turning the tap 43 degrees [(105+45*x/360)/(1+x/360)=98.6]. Extra well done, so, to: John Bowen, consultant, Bromsgrove, UK; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, UK; Anthony Cutler, OTR Global, Australia; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn Thailand; François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, France.

SEPTEMBER 2016

Every now and then our judging panel chooses to award our top 'prize' to a promising new entrant. So, for weighing in first with the correct answers to our last two Brainteasers, well done to: François Joua of Konimpex, our new Brainiac of the Month

Question 4: Double back

What is the smallest number, besides 1, that is one less than twice its digits reversed?

Answer: No problem, as long as you read this one carefully. Well done to all who answered 73: François Joua, business developer, Konimpex Sp. Z O.O, Lyon, France; Amparo Botella, Ismael Quesada SA, Spain; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; John Bowen, consultant, Bromsgrove, UK; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn,Thailand; Stephan N Cortel, Mesnac, USA; Hugo Ernesto Vera, adscripto, proyectos expansion, FATE S.A.I.C.I., Buenos Aires, Argentina; Shinichi 'Steve' Yoshida, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn,Thailand.

Question 3: 60 in 60

It takes six technicians to change six tires in six minutes. How many technicians does it take to change 60 tires in 60 minutes?

Answer Most people saw through this straight away, though one of the first replies in said the question was too easy, but gave the wrong answer! Anyway, well done to all of the following readers who correctly answered 6: François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, France; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Rayong Province, Thailand; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; John Bowen, consultant, Bromsgrove, UK; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Québec, Canada; Hugo Ernesto Vera, Adscripto, Proyectos Expansión, FATE S.A.I.C.I., Buenos Aires, Argentina; Tony Cutler, OTR Global, Australia; Dr Mohamed Hassan, R&T executive director Mesnac Americas Co. Ltd, Akron, Ohio, USA; Shinichi 'Steve' Yoshida, SSWT, Japan; Himesh Shah, Sonil Ventilfabrik, GIDC Indl. Estate, Jamnagar, India; Anton Markin, senior financial analyst EMEA, Goodyear, Diegem, Belgium.

Question 2: Next number

What is the next number in the following sequence 5, 10, 26, 50, 122…?

Answer: Well done to readers who saw through this thinly disguised prime-number sequence and worked out the answer at 170: Amparo Botella, Ismael Quesada SA, Spain; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Rayong Province, Thailand; John Droogan, UK business manager, MegaChem UK Ltd, Monmouthshire, UK; David Mann. manager rubber technology, SI Group, Béthune, France; Marzio Bussola, Parker Hannifin Manufacturing Srl,  Italy; Stephan N Cortel, Mesnac, USA. Chris Kelly, Cabot Corp.

Question 1: Four-digit dilemma

What four-digit number has digit 1 three less than digit 4, which is one more than digit 2, which is twice digit 3, which is not a prime number and is one more than one-third of digit 4?

Answer: Code-breaking seems to be a strong-point among ERJ readers, judging at least by those who came up with the correct answer 6849. Quickest to reply were: Michael Simpson, research and development engineer, Trelleborg Industrial AVS, Leicester, UK: Amparo Botella, Ismael Quesada SA, Spain; Dave Lawson, product change coordinator, HTV Elastomers, Polymers & Engineered Materials (Healthcare), Dow Corning Ltd, Barry, UK; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; John Bowen, rubber industry consultant, Bromsgrove, UK; François Jouan, business developer, Konimpex Sp. ZOO, Lyon, France; David Mann, manager Rubber Technology, SI Group, Béthune Cedex, France;  Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Rayong Province, Thailand; Thierry Montcalm, R&D chemist, Soucy International Inc., Québec, Canada; Stephan N Cortel, MESNAC, USA.

August 2016

If we do have a prize for the overall winner at the end of this year (this is under discussion), one of the top candidates will be Yuichi "Joe" Sano, who outperformed the field throughout August - not least with Question 5 - to become our new Brainiac of the Month

Question 5: Flora & fauna

Which Rio Olympics medal-winning countries have an image or representation of a living organism in their national flags, and what was the total number of medals won by these countries?

Answer: If there were marks going for style and effort, the clear winner would be Ian Jones, managing director, Contitech, Power Transmission Group, ContiTech United Kingdom Ltd, Wigan, UK, who supplied this excellent table. However, we took the liberty of adding a few extra medal-winning countries (in red) missing from the original table. The additions brought the medal total to 89, as answered only by Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Rayong Province, Thailand. Fine efforts also by Amparo Botella, Ismael Quesada SA, Spain and John Bowen, rubber industry consultant, UK.

Note: After much debate, our judging panel decided that the P0lish flag with a coat of arms was not that country's official flag.

Question 4: Three-person painting puzzle

Ashwin is painting the office reception area. He can do the job in 3 hours 40 minutes. Half way through he is joined by Hamish, who paints half as fast as Ashwin. Then 3 hours into the job, Alan starts lending a hand, painting at half the speed of Hamish. How long did it take to paint the reception?

Answer: A few twists and turns to this teaser but not enough to stop our expert readers working out the correct answer:  3 hours 2 minutes 51 seconds. Well done to: John Bowen, rubber industry consultant, Bromsgrove, UK; François Jouan, business developer, Konimpex Sp. Z O.O, Lyon, France; Thierry Montcalm, R&D chemist, Soucy International Inc., Québec, Canada; Stephan Cortel, Mwesnac, USA; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; Aditya Biswas, automobile researcher, Segment Y; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy.

Question 3: Rock of ages

Ageing rock group the Kings of Oblivion have worked out their takings from a weekend concert at €95, There were 100 tickets sold, with students paying €0.50; over 60's,  €2.50; and all others charged £10 each, How many students, over 60's, and 'all others' went to the concert?

Answer: Less mind-bending that the rock group's name suggests: the answer was 85 students (€42,50), 13 over 60’s (€32,50) and 2 ‘all others’ (€20). Well done to: Ronald Meyns, strategic account manager, Goodyear EMEA, Rockwell Automation, Hamburg, Germany; John Bowen, rubber industry consultant, Bromsgrove, Worcestershire, UK; Thierry Montcalm, R&D chemist, Soucy International Inc., Québec, Canada; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Rayong Province, Thailand; Karl Heinz Sandholzer, product management vice president, Saurer Germany GmbH & Co. KG, Kempten, Germany; Michael Easton, sales and marketing director, Globus, Manchester, UK; Michael Simpson, research and development engineer, Trelleborg Industrial AVS, Leicester, UK.

Question 2: Rigged test

At a rubber gasket manufacturer’s QC lab, a 60cm-diameter ring, made from 2cm-thick metal rod, is fixed horizontally on a test-rig and 8cm balls are dropped randomly from a container above. The test is to see if each ball is more likely to hit the ring or fall through without hitting it. Which outcome is more likely?

Answer: Not too many on target here:. Each ball is more likely to hit the ring When Ring ID=60cm: the white area= 44x44xpai/4; the blue area=(80x80-44x44)xpai/4. The blue area, so, is much bigger than the white area, so  each ball has more chance to hit the ring than to go through  the ring.

Very well done to Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Thailand (many thanks for the diagram); and John Bowen, rubber industry consultant, Bromsgrove, Worcestershire,UK.

Question 1: High five

To celebrate five years in business, the manager of a rubber manufacturing company decides to order pizzas, in the shape of a regular pentagon, for the staff. The local pizzeria gives him two choices: pizzas with 5-inch sides at €6.00 each or those with 7-inch sides for €7.50. Which size is the best value for money?

Answer: The total area of pentagon with 5” side is approx. 43 SQ in, therefore cost is 600/43 = €0-14/SQ in. Total area of pentagon with 7” side is approx. 84 SQ in, therefore cost is 750/84 = €0-09/SQ in. Pizza with 7” sides is best value. Well done to: John Droogan, UK business manager, MegaChem UK Ltd, UK, John Bowen, consultant, Bromsgrove, Worcestershire, UK; Karl Heinz Sandholzer, product management vice president, Saurer Germany GmbH & Co. KG, Kempten, Germany; Thierry Montcalm, R&D chemist, Soucy International Inc, Québec, Canada; Stephan N Cortel, Mesnac, USA, Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Thailand; Amparo Botella, Ismael Quesada SA, Spain; Wanda Welch, research & development manager, ecore international, Lancaster, Pennsylvania, USA.

July 2016

A clear result this time: while Question 1 left almost everyone floundering, our winner worked steadily though the maths and was first to identify the binary sequence behind the series of numbers. Extra well done to UK rubber industry consultant John Bowen, our new Brainiac of the Month.

Question 4: Presidential puzzle

The five candidates seeking to be elected president of a new rubber industry association have attracted a total of 320 votes. How many votes did the lowest placed candidate receive if the winner's margin over the other four was 9, 13, 18 and 25?

Answer: If 320 = x + (x-9) + (x-13) + (x-18) + (x-25) then x = 385/5 = 77 and the candidate who came last got (77-25) 52 votes. Our quiz poll toppers this week are: Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong, Thailand; Marzio Bussola, Parker Hannifin Manufacturing Srl – Italy; Amparo Botella, Ismael Quesada SA, Spain; Thierry Montcalm, R&D chemist, Soucy International Inc., Québec, Canada; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Ian. P. Jones,  managing director, Continental Division Contitech, Power Transmission Group, ContiTech United Kingdom Ltd, Wigan, UK; Inna Stein, trading, RCMA Europe BV, Zaandam, The Netherlands; Karl Heinz Sandholzer, product management, vice president, Saurer Germany GmbH & Co. KG, Kempten, Germany; Mohamed Hassan, R&T executive director, MESNAC Americas Co., Ltd, Akron, Ohio, USA;  Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium.

Question 3: What’s common?

What do ERJ, LA and Eric Blair have in common?

Answer: They contributed to the first time an ERJ brainteaser failed to receive a “completely” correct answer. The answer was 84 – reference to ERJ’s first issue in 1884, Los Angeles 1984 Olympics and the famous work of Eric Blair (George Orwell) 1984.

Some, including Jon Cutler, materials development manager, Trelleborg Sealing Solutions Tewkesbury, UK; David Mann, manager rubber technology, SI Group, Béthune, France and John Burrows, a consultant to the tire and rubber reinforcement industries came close by coming up with the figure 1984, while Yuichi "Joe" Sano of Sumiden Steel Wire (Thailand) Co. Ltd pointed to ERJ’s 100th anniversary in 1984.

Question 2: Mazy manager

The boss of a large rubber chemicals plant commissions a landscape gardener to plant lines of high bushes at the factory site. The gardener first plants a line running 100 paces east. From the end of that line he plants a line 100 paces north, then 100 west, 98 south, 98 east, 96 north, 96 west, and so on. This made a square spiral path 2 paces wide. How long is the path, if the chemicals boss walks down the middle of it?

Answer: Readers seem to have taken different approaches to this problem, but the official answer is 5,000 paces, as only Yuichi "Joe" Sano  of Sumiden Steel Wire (Thailand) Co. Ltd worked out:

99+98+98+96+96+94+94----------+6    +6  +4  +4   +2  +2  +1

+) 1  +2  +2  +4  +4   +6   +6 ----------+94+94+96+96+98+98+99

--------------------------------------------------------------------------------------

100+100+100+100+100+100--------+100+100+100+100+100

=100x100=10000

10000/2=5000

Question 1: You cannot be series

In the sequence 1, 3, 7, 15, 31, 63 what do the numbers have in common, apart from the obvious arithmetical progression?

Answer: Our quiz-master was joyful at the start of the week, having seemingly stumped all of the best brains in the global rubber industry. That was until leading UK consultant John Bowen – though he said his head was left hurting –  and, a couple of days later, John Droogan, UK business manager at MegaChem UK Ltd, identified this as the binary sequence: 1,11,111,1111,11111, 111111, Others got there after  a few attempts or came close with (2 to the power of n) -1. So well done also to: Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Thailand ; Biswajit Paul, global product technology manager, Birla Carbon -  Rubber Carbon Black Business, India; John D Burrows, consultant, France; and Stephan N Cortel, Mesnac, USA.

June 2016

Perhaps it's a bit random, and hoping our regular readers don't mind, but the judging panel has decided to give this month's award to a first-time entrant from Germany, a country that shows up surprisingly rarely in the ERJ Brainteaser 'winners list'. Well done, so, and welcome to Ronald Meyns of Rockwell Automation, our new Brainiac of the Month.

Question 5: Simple Sum

64 – 8 ÷ 1/8 – 1 = ?

Answer: Using BODMAS, (or PIMDAS in some countries) the correct order for calculations is:  Brackets, Orders, Division, Multiply, Add, Subtract] making the answer  -1. Well done to: David Mann, manager rubber technology, SI Group, Béthune, France;  John Burrows, consultant to the tire and rubber reinforcement industries, France; John Bowen, consultant,  Bromsgrove, Worcestershire, UK; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; Julien Coupechoux, product manager, Dipropneu, Bondoufle, France; Otakar Vašák, Trelleborg Sealing Profiles, (no work/location details supplied); Ronald Meyns, strategic account manager Goodyear EMEA, Rockwell Automation,  Hamburg, Germany; Thomas Bell, S & T Group LLC, (no work/location details supplied); Sebastian Barbe, Germany (no work/location details supplied); Matthew Friel, leader, corporate development, Johns Manville, a Berkshire Hathaway company, Denver, Colorado, USA.

Question 4: Missing Element

Find the missing element in the following sequence: B, N, Na, _, Cl, K, V...

Answer: All you needed was a periodic table to spot that Al (aluminium) represents the missing prime number in the sequence: Well done to: John Bowen, consultant,  Bromsgrove, Worcestershire, UK; David Mann, manager rubber technology, SI Group, Béthune, France; Amparo Botella, Ismael Quesada SA, Spain; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Rayong Province, Thailand; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK;  Stephan N Cortel, Mesnac, USA;  Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Ian. P. Jones, managing director, Continental, Division Contitech, Power Transmission Group, ContiTech United Kingdom Ltd, Wigan, UK; Jon Cutler, materials development manager, Trelleborg Sealing Solutions, Tewkesbury, UK; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium; Karl Heinz Sandholzer, product management, vice president, Saurer Germany GmbH & Co. KG, Kempten, Germany.

Question 3: Robot Riddle

In a football test lab, a robot is drawing out samples from; batch A, which has 7 red footballs and 1 blue, and batch B, which has 7 blue footballs and one red. After selecting one of the batches, the robot randomly draws out a blue ball and puts it back. What is the probability that the next ball randomly drawn from the same batch will also be blue?

Answer: Maybe not as tricky as it seemed and well done to the following readers who answered 50%: Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; David Mann, manager rubber technology, Béthune, France; Stephan N Cortel, Mesnac, USA; John Bowen, consultant, Bromsgrove, Worcestershire, UK; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK.

Question 2: Plane puzzle

From takeoff, a passenger jet starts climbing at a steady rate. After two minutes, the cockpit instruments show that it has reached an altitude of 1000 metres and has travelled a distance of 3km. At what angle is the jet climbing?

there were two correct answers here: depending on whether the distance covered was interpreted as ground-distance – ~18.4 degrees; or flight-path ~19.5 degrees. Well done to David Mann, manager rubber technology, SI Group, Béthune, France; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; John Droogan,UK business manager, MegaChem UK Ltd, Caldicot, UK; Daniel Cortarelli, senior technical sales manager - distribution / oil & gas, Precision Sealing Systems, Houston – Texas, USA; Amparo Botella,  Ismael Quesada SA, Spain; John Bowen, consultant, Bromsgrove, UK; T N Dahal, no details given, Nepal; Himesh Shah, Sonil Ventilfabrik, Jamnagar. India: Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy.

SPECIAL ANNOUNCEMENT: ERJ held a prize draw for all entrants to the Brainteaser over the 14 weeks between 8 Feb and 27 May. The prize of a €50 Amazon voucher from ERJ, and a VIP gifts bag -  kindly donated by Continental and Nexan Tire - went to an entrant for Week 2 of those 14 weeks  - as drawn last week by our judging  panel. The winner was drawn from the entrants for that Brainteaser (Pipeline Puzzle), this week, and so well done to: David Mann of SI Group in France - prize on the way - and better luck next time to all our Brainiacs.  

Question 1: Roll reversal

A truck has been used as a tire-test vehicle for quite some time, as can be seen from the kilometre-reading on the dashboard, 72927km - palindromic number.What is the minimum number of kms the truck would need to travel in order to form another palindromic number?

Answer: Not our toughest ever teaser, but still not everyone correctly worked out that the truck would need to travel 110km and clock up 73037km. Well done, so, to: Amparo Botella, Ismael Quesada S.A, Spain; John Droogan, UK business manager, MegaChem UK Ltd, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; David Mann, manager Rubber Technology, SI Group, Béthune Cedex, France; John Burrows, consultant to the tire and rubber reinforcement industries, France; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; SK Lee, Petronas, Malaysia; V.Srinivasan, partner, 6T Services, Gopalapuram. Chennai, India; Stephen Fulton,. R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge Belgium.

May 2016

There can only be one winner this month. With his accurate and speedy replies to the fairly tough range of challenges posed over the last four weeks, well done to UK-based industry consultant John Bowen, the new ERJ Brainiac of the Month.

(A prize draw for all Brainteaser entrants over the past couple of months will be made next week)

Question 4: Simple equation

(w/x) / (y/z) - (z/y) / (x/w) = ?

Answer Sorry for the blip with the equation on day 1 and well done to well done to the following readers who answered 'Zero': John Bowen, consultant, Bromsgrove, Worcestershire, UK; Henrik Marits, sales manager Nordic SC, Nynas, Stockholm, Sweden; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; Marzio Bussola,  Parker Hannifin Manufacturing Srl, Italy; David Mann, manager rubber technology, SI Group, Béthune, France;  Tom Bell, marketing & business services in elastomers, S & T Group LLC, Houston, Texas, USA.

Question 3: Beer or Brexit

As a cunning ploy to encourage his UK workers to vote to stay in the EU, a chemical-plant manager has installed a UK- and a European-style beer tap in the company canteen. The UK tap fills a pint glass in 12 seconds, the European version fills a litre glass in 15 seconds. Approximately how long would it take to fill a pint glass using both taps simultaneously, together?

Answer: Several readers seem to have used the US pint (473.2 cm3) here. But as the chemical plant was clearly in the UK, the judges have only accepted the UK pint conversion of 568.26 cm3, making the answer around 5 seconds (eg 568.26/(568.26/12+1000/15): Well done to John Bowen, consultant, Bromsgrove, Worcestershire, UK; Anna Anderzén, export market manager, Elastocon AB, Tvinnargatan, Brämhult, Sweden; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd,, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province, Thailand; Stephan Cortel, Mesnac, USA.

Question 2: Big bang theory

Scientists at Lunney Latex Co are trying to develop the world's first perfectly spherical balloon. As part of their research, a simulated spherical balloon is inflated at a rate of 4 cubic centimetres per second. What is the rate of increase of the radius, when this radius is 3cm?

Answer: Should have called this 'small bang theory', as the number of replies went right down and we only had two readers with the correct answer: around 0.35cm/second (1/9pi). Extra well done so to John Bowen, Bromsgrove, Worcestershire, UK; and Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Ltd, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong Province,Thailand

Question 1: Rubber capital

Following on from our popular 'Cross country challenge' teaser: how many capital cities (ie of countries) can you create from the letters in:

Acrylonitrile-butadiene

Answer:  Our judges came up with 14 capital cities: Beirut, Berlin, Bern, Cairo, Canberra, Dili, Dublin, Luanda, Nairobi, Rabat, Tallinn, Tirana, Ulan Bator, Yaounde.

The panel ruled out: Cayenne, French Guyana (a department of France), Yaren, Nauru (not classified as a capital city); Laayoune, Western Sahara (status disputed).

The top replies came from: John Bowen, consultant, Bromsgrove, Worcestershire, UK (13); Teodora Todorova, sales & purchasing assistant, Eurochimind, Italy (13), Amparo Botella, Ismael Quesada SA, Spain (12); and Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Amphur Pluakdaeng, Rayong province, Thailand (12).

April 2016

With respect to all readers who consistently came up with correct answers, this month's overall winner stood out by identifying 41 countries, including Liechenstein, hidden in the names of the three tires makers in Question 3. Very well done to  Magnus Lagerqvist of Erteco Rubber & Plastics AB in Sweden, our new Brainiac of the Month.

Question 4: Missing letter

Which letter is missing from the following series?

S, M, H, D, _ , M, Y?

Answer: After last week’s lengthiest-ever answer, this was the shortest: ‘W’ for the sequence  : second, minute, hour, day, WEEK, month, year.

Well done to: John Bowen, consultant, Bromsgrove, Worcestershire, UK; Amparo Botella, Ismael Quesada SA, Spain; David Mann, manager rubber technology, SI Group, Béthune, France; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co., Amphur Pluakdaeng, Thailand; John D Burrows, consultant, France;  John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, Monmouthshire, UK; Mike Tooke, 2gb Consulting, UK; Trisha Kerr, Barbe (UK) Ltd, UK; Karl Heinz Sandholzer, product management, vice president, Saurer Germany GmbH & Co. KG, Kempten, Germany; and Doug White, Rydel, Australia.

As the question could be decoded in other ways, well done also to SK Lee, Petronas, Malaysia; Marzio Bussola,  Parker Hannifin Manufacturing Srl, Italy; and Teodora Todorova, sales & purchasing assistant, Eurochimind, Italy .

Question 3: Cross country challenge

Which country names can be made by combining any of the following 30 letters?

Bridgestone

Hankook

Michelin

Answer: The judges’ list comprised: Benin, Cameroon, Chad, Chile, China, Colombia, Comoros, Congo, Denmark, Dominica, Estonia, Gabon, Ghana, Greece, Haiti, Iceland, India, Indonesia, Iran, Ireland, Israel, Kiribati, Laos, Lebanon, Lesotho, Liberia, Liechtenstein, Mali, Malta, Micronesia, Monaco, Mongolia, Montenegro, Netherlands, Niger, Nigeria, Oman, Senegal, Serbia, Togo, Tonga.

(After much debate, the panel excluded Greenland as not a fully independent country, and Bosnia and Sao Tome as these were not full country names. (Republic of the) Congo, though, was included.

With all 41 countries,the winner was Magnus Lagerqvist of Erteco Rubber & Plastics AB Stockholm, Sweden. His list of 41 countries, including Lichenstein, and just beat off strong competition from: Eur Ing John Bowen, consultant, Bromsgrove, UK; Amparo Botella, Ismael Quesada SA, Spain; Yuichi "Joe" Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Amphur Pluakdaeng, Rayong Province, Thailand;  Teodora Todorova, sales & purchasing assistant, Eurochimind, Italy.

This was probably our most time-consuming teaser ever, so an extra entry for each of these readers in the Brainteaser Prize Draw to be held during the Future Tire Conference, 24-25 May at Reifen 2016 in Essen, Germany.

Question 2: Locked bike

To open the combination lock on her bike, Jane needs to work out the missing number in this series. What is it?

56, 11, 83

88, 16, 97

77, ??,  59

Answer: Back down to earth from the near-cosmic introspections of last week. Well done to all our code-breakers who answered 14: John Bowen, consultant, Bromsgrove, Worcestershire, UK; John Droogan, UK business manager, MegaChem UK Ltd; Caldicot, Monmouthshire, UK; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; Teodora Todorova, sales & purchasing assistant, Eurochimind, Italy; Jon Cutler, materials development manager, Trelleborg Sealing Solutions Tewkesbury, UK; Marzio Bussola,  Parker Hannifin Manufacturing Srl, Italy;  Gerardo Sica, technical services manager, Aditya Birla; Keaton Goedert, Invista Intermediates; Dave Lawson, product change coordinator – HTV Elastomers, Polymers, Engineered Materials (Healthcare) & Feedstocks, Dow Corning Ltd, Barry, Vale of Glamorgan, UK; Yuichi “Joe” Sano, Sumiden Steel Wire (Thailand) Co. Ltd, Amphur Pluakdaeng, Rayong Province, Thailand; Stefan Böttcher, Troester GmbH & Co. KG, Rubber Machinery Division – sales, Hannover, Germany;   Biswajit Paul, global product technology manager, Rubber Carbon Black Business, Birla Carbon, Taluka Panvel, Maharashtra, India; SK Lee, Petronas, Malaysia; Vullo Ignazio, Brenntag SpA, Milano, Italy; Steve Cuddihy, senior engineer, Goodyear Tire & Rubber Co. Akron, Ohio, USA.

Question 1: Take time

How many seconds, if any, are you left with when you subtract 24 hours from a day?

Answer: Sorry, this was not meant to be a trick question. However, given the wide variation in interpretation of a ‘day’, the judging panel thought it best just to list the full range of solutions provided. Many thanks for all the mental effort put in:

- David Mann, manager Rubber Technology, SI Group - The mean day length is 86400.002 seconds, so 0.002 seconds left

- John Bowen, Consultant The  actual length of a day is taken as 23h 56min 4sec: So to take away 24 hours leaves us -3min 56secs or -236 seconds

- Marzio Bussola, Parker Hannifin Manufacturing S.r.l. – Italy: The answer to the above mentioned question depends on the period of the year in which you make this calculation, for example in March and September the Sun takes less time to make an apparent revolution than it does in June and December; 24 "hours" of solar time can be 18 and 21 seconds less or 13 and 29 seconds more than 24 hours of clock time. In the other months this difference is lower and close to zero.

- Magnus Lagerqvist, Erteco Rubber & Plastics AB: 59 seconds are left when you subtract 24 hours from a day: We have a leap year every four years and thus it becomes (24 * 60 * 60)/4 seconds more each year (365 days) = 21,600 seconds. 21600/365 = 59.17808219 seconds. Every day is therefore about 59 seconds more than 24 hours.

- Stephan N Cortel, Mesnac North America, USA: Depends on the definition of day.  If you are referring to a stellar day then there would not be a remainder, in fact there would be a deficit or negative.  (23 hours, 56 minutes 4.1 seconds minus 24 hours = -3 minutes 4.1 seconds) or -184.1 seconds.  However if you are referring to a Solar day then the remainder would be 0.000036 seconds

- Hans-Bernd Luechtefeld, PHP Fibers: About 59 seconds

- Çhris Twigg, Black Bear Carbon BV: 57.1095 seconds 57.33 seconds

- John Droogan, MegaChem UK Ltd: 57.33 seconds

March 2016

It was neck-and-neck among our most consistent performers going into the final week of March. However, breaking free from the elite pack at Question 5, was Marzio Bussola, of Parker Hannifin Manufacturing in Italy, the new Brainiac of the Month.

Question 4: Dandelion dilemma

At a test site for growing dandelions for the rubber industry, scientists mark out points A, B and C on a horizontal piece of ground. The distances between A and B is 19m, B and C 16m and C and A 21m.  What is the size on the angle ACB?

Answer Well done to the following readers who worked out that the angle at 60 degrees: John Bowen, consultant, Bromsgrove, UK; David Mann, manager rubber technology, SI Group, Béthune, France; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co. Ltd, Amphur Pluakdaeng, Rayong province, Thailand.

Question 3: Cliff hanger

On board his yacht, the skipper measures the angle of elevation of the top of a cliff as 12 degrees. He sails 800 metres directly towards the cliff and then measures the elevation of the top of the cliff as 65 degrees. What is the distance from the second position of the boat to the top of the cliff and what is the height of the cliff?

Answer: Are we making these too tough? Only a select few worked out that the distance from the second position of the yacht to the top of the cliff is 208.3m and the height of the cliff is 188.8m. Extra well done to: John Bowen, consultant, Bromsgrove, Worcestershire, UK; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co., Ltd; Thailand; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy.

Question 2: Dice Dilemma

David and Domenic play a game with two dice, without numbers. Some of the faces are painted green and the others blue. Each player throws the dice in turn. David wins when the two top faces are the same color. Domenic wins when the colors are different. Their chances are even. The first die has 5 green faces and 1 blue face. How many green and how many blue are there on the second die?

Answer: A bit easier this week, but not everyone worked out that the second dice has 3 green and 3 blue faces. Anyway, well done to: Jon Cutler, materials development manager, Trelleborg Sealing Solutions Tewkesbury, UK; Marzio Bussola,  Parker Hannifin Manufacturing Srl,  Italy; John Bowen, consultant, Bromsgrove, UK; ; Amparo Botella, assistant manager, Ismael Quesada SA, Spain; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; David Mann, manager rubber technology, SI Group, Béthune, France; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co., Ltd; Thailand.

Question 1: Family of squares

Our son said to me, "I will become precisely X years old in the year X squared". (Of course, he did give me the value of the whole number X). I replied, "My own father made a similar statement when I was a lad".How old was my father when our son was born? (My father's birthday comes before my son's each year.)

Answer: This one foxed many readers - even our regulars - so well done to the following, who worked out that the father was 88 years old when his grandson was born: John Bowen, consultant, UK; Amparo Botella, assistant manager, Ismael Quesada SA, Spain; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; David Mann, manager rubber technology, SI Group, Béthune, France; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co., Ltd; Thailand; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden.

February 2016

Anyone who answered all four questions, was a strong candidates for this month's award. But for his beautifully worked out solution to the Tricky Triangle (see diagram below), using Heron's formula, congratulations to Yuichi "Joe" Sano of Sumiden Hyosung Steel Cord, the new ERJ Brainiac of the Month.

Question 4: Tricky triangle

Design engineer Rathi has cut a scalene triangle (if you don't know, look it up...) out of a square sheet of hard rubber. The longest side of the triangle is 29cm more than the shortest side, and the third side is 15cm longer than twice the shortest side. Each of its sides is a whole number of cms, and she tells me that its area in square cms is twice its perimeter in cms.

If the original sheet was 30 cms square, what are the lengths of the three sides of the trianglular cut-out?

Answer  This was clearly one of our trickiest teasers, so well done to the following readers who worked out that the lengths of the sides are: 10cm, 39cm and 35cm: John Bowen, consultant, UK; John Burrows, consultant to the tire and rubber reinforcement industries, France; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord, Thailand;  David Mann, manager rubber technology, SI Group, Béthune, France  Biswajit Paul, global product technology manager, Rubber Carbon Black Business, Birla Carbon, Taluka Panvel, Maharashtra, India; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Amparo Botella, assistant manager, Ismael Quesada SA, Spain; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Sweden.

Question 3: Track test

At a tire testing track, a car was driven around a 6km track at 154 km per hour for 3km, 168 km/hr for 1.5km, and 210 km/hr per hour for 1.5km. What was the approximate average speed of the car for the entire 6km?

Answer: The official correct answer is approximately 169km/hr. Well done to: Inna Stein, Wurfbain, Zaandam, The Netherlands; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Sweden; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; Amparo Botella, assistant manager, Ismael Quesada SA, Spain; Biswajit Paul, global product technology manager, Rubber Carbon Black Business, Birla Carbon, Taluka Panvel, Maharashtra, India; John Burrows, consultant to the tire and rubber reinforcement industries, France; Carlos Sorentino, technical director, Recycled Fuel Technologies Inc, Australia; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord, Thailand; Himesh Shah, Sonil Ventilfabrik, India.

Special announcement: As a thank you, ERJ is arranging a series of small prizes for readers replying to the Brainteaser in the ERJ Daily Newsletter. The first award (prize to be announced) will be made during the Reifen /RubberTech/Future Tire Conference event, being staged 24-27 May in Essen, Germany.  The winner’s name will be drawn, by the editor, from a closed box containing every correct Brainteaser answer received each week from 8 Feb up to 25 May.

Question 2: Pipeline puzzle

At a synthetic rubber plant, there are four pipelines feeding a giant chemical feedstock tank. The first line can fill the entire tank in two days, the second – in three days, the third – in four days, and the last one can fill the tank in 8 hours. How long will it take to fill the tank using all four pipelines together?

Answer: We’ve accepted any estimate in or around 5hrs, 52 minutes. Extra well done to: David Mann, manager rubber technology, SI Group, Béthune, France; John D Burrows, consultant, France; Amparo Botella, assistant manager, Ismael Quesada SA, Spain; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co. Ltd, Tambol Mabyangporn, Rayong, Thailand; John Droogan, UK business manager, MegaChem UK Ltd, Caldicot, UK; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; Dr Carlos Sorentino, technical director of Recycled Fuel Technologies Inc, Australia; Don.B.Ilapperuma, chairman/CEO, Imperial Rubber Industries (Pvt) Ltd, Sri Lanka.

Question 1: Help Hamish 2

Much in-demand apprentice Hamish receives two new job offers - both 10-year contracts. Firm A's has a starting salary of £22,000 and an annual pay rise of 4.0 percent, while Firm B's starts at £25,000 with an annual pay rise of 3.0 percent. Which contract has the most earning potential?

Answer: Firm B's offer has the most earning potential: the total sum is £286,597 $ instead of  £264,134 $ from Firm A's. Well done to: Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy; David Mann, manager rubber technology, SI Group, Béthune, France; Amparo Botella, assistant manager, Ismael Quesada SA, Spain; John D Burrows, consultant, France; Biswajit Paul, global product technology manager, Rubber Carbon Black Business, Birla Carbon, Taluka Panvel, Maharashtra, India; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co., Ltd; Thailand;  Saranan Thirumoolan, design engineer, Ferrabyrne Ltd, Littlehampton, UK; Dr Carlos Sorentino, technical director of Recycled Fuel Technologies Inc., Australia.

January 2016

The judging panel has decided that the first award of 2016 should go to the 'winner' of the toughest teaser, which this month was question 3.

Very well done to Amparo Botella of Ismael Quesada our new Brainiac of the Month

Question 4: Help Hamish 1

Rubber factory apprentice Hamish has a tough decision to make. He has been told that if he stays with his current employer he will be earning £28,000 a year in 10 years time. However, he has been offered a job elsewhere with a starting salary of £20,000 and an annual pay rise of 2.5 percent each year. Help Hamish decide: should he stay or should he go?

There were a few questions back about this one, some suggesting that we needed to give the starting salary in his current job. The following, readers, though were able to work out that Hamish should stay as his salary would just be around £25,600 after 10 years: John D Burrows, consultant, France; John Bowen, consultant, Bromsgrove, UK; Biswajit Paul, global product technology manager, Rubber Carbon Black Business, Birla Carbon, India; Amparo Botella, assistant manager, Ismael Quesada .SA, Spain; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co. Ltd, Amphur Pluakdaeng, Rayong Province, Thailand; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden: Marzio Bussola, Parker Hannifin Manufacturing S.r.l. – Italy; Stephan N Cortel, MESNAC Americas Co.,Ltd, USA.

Question 3: Prime puzzler

What number comes next in the sequence: 61, 691, 163, 487, 4201, ?

Answer: Only a select few readers came up with the answer - 9631 is the next prime number that turned back (1369 is perfectly squared). Very well done to: Amparo Botella, assistant manager, Ismael Quesada SA, Spain; John Bowen, consultant, Bromsgrove, UK; , Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; David Mann, manager rubber technology,, Béthune, France; Stephan N Cortel, MESNAC Americas Co, Ltd, USA; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co., Ltd, Thailand.

Quesrtion 2: Rubber Parts Puzzle

A rubber parts producer buys in three new injection moulding machines to help meet a new order. Two of the new machines are able to meet the order at a rate of 1/12th of the total a week and the other at 1/24th a week. If the existing four machines can each produce 1/36th of the order a week, approximately how long will it take the company to supply the order with all seven machine operating at full capacity?

Answer: Around 22 days, quite a quick turnaround really. Well done to: Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; David Mann, manager rubber technology, SI Group, Béthune, France; John Bowen, consultant, Bromsgrove,Worcestershire, UK; Yuichi "Joe" Sano, Sumiden Hyosung Steel Cord (Thailand) Co., Ltd. Amphur Pluakdaeng, Rayong Province, Thailand; Biswajit Paul, global product technology manager, (rubber carbon black business, Birla Carbon) / SKI Carbon Black (India) Pvt Ltd, Raigad, Maharashtra, India; Marzio Bussola, Parker Hannifin Manufacturing Srl, Italy, Thierry Montcalm, chemist, development leader, materials engineering, Rubber Tracks Division, Soucy International inc., Quebec, Canada; Amparo Botella, assistant manager, Ismael Quesada SA, Spain; Stephan Cortel, MESNAC Americas Co. Ltd, USA; Magnus Lagerqvist, Erteco Rubber & Plastics AB, Stockholm, Sweden; Anahit Pivazyan, i.A. executive assistant to president Europe & Africa Birla Carbon, Birla Carbon Europe, Hannover