ERJ Brainteaser Results: April - January 2018

APRIL

With respect to all our other great contestants, there is one standout winner this time around. For single-handedly defeating our question-master in week 2 and 3, huge congratulations go to:

                                    Yuichi (Joe) Sano our new Brainiac of the Month.

Question 5: Cake-cutting challenge

Answer: Not such a piece of cake this week, as we had quite a few wrong answers. Well done so to the following readers, who worked out that the cake should be cut 4.126 cm –   20*20*20=2*(20-x)*(20-x)*(20-x) – above the base: David Mann, manager rubber technology, SI Group, Béthune, France; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK;  Paul Knutson, textile, engineer, Timken Belts, Springfield, Missouri, USA; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami Works, special steel wire division; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge Belgium.

Question 4: Chance en-counter 3

Well done in order of answer-arrival to: Thierry Montcalm, R&D Chemist, Soucy Techno, Canada; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge Belgium; Paul Knutson, textile, engineer, Timken Belts, Springfield, Missouri, USA; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami Works, special steel wire division.

Question 3: Missing Link

6. _ , 15, 16, 23, 24.

Clues given during the week: Try adding prime numbers...Then easy as 1, 2, 3, 4, 5... The answer is not 7... The next two numbers in the sequence are 31 and 32.

Seems like Simon might well have a long walk home and should next time set an easier code to work out…

Question 2: Coded message

What does this coded message say?

d e i a o b n s t r t e h a e r

Bonus question: What links the following numbers?:

1759, 232, 30,000,000, 1725

Answer: Pure genius again from Yuichi, who was also the only reader to work out ‘Guinness’ as the answer to our Bonus question.

Question 1: What time?

Complete the time sequence: 12:03; 11:14; 09:26; 06:39…

MARCH 2018

There were some strong candidate for our top award this time, but what impressed our panel most were some clever alternative answers given for Question 3.

Congratulations, therefore, to: Hans-Bernd Lüchtefeld of PHP Fibers, our new Brainiac of the Month!

Question 4: Dave's donuts

Dave likes donuts a lot but has gone on a diet. He now aims to eat less than 30 donuts a week. So, on Monday, he ate some donuts; on Tuesday, half as many as on Monday; On Wednesday, 5 donuts less than Tuesday; and on Thursday, 9 donuts. For the final three days, Dave ate no donuts at all. If Dave met his target of eating less than 30 that week, what is the biggest number of donuts he could have eaten on Monday?

Answer: The correct number was 12, for this, not our most difficult (or healthiest) ever, teaser, However, still made for a tidy equation, as sent in by Yuichi Sano: x+0.5x+(0.5x-5)+9

Well done to: David Mann, manager rubber technology, SI Group, Béthune, France; Andrew Beasley, product analyst, Hankook Tyre UK Ltd, UK; Jon Cutler, materials development manager, Trelleborg Sealing Solutions Tewkesbury, UK; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; John Bowen, consultant, Bromsgrove, Worcestershire, UK; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Ralf Ortmayr, senior pricing analyst, Toyo Tire Europe GmbH, Willich, Germany; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami, Japan.; Randa Tharwat, import manager, Nacita Automotive, Cairo, Egypt.

Question 3: Not 2 easy

Using any combination of mathematical signs, symbols and/or functions, can you make 5 using only two 2s?

Answer: Never mind the ‘correct’ answer (displayed below), some readers also came up with some more inventive solutions. Among these was Hans-Bernd Lüchtefeld’s 2 + 2 + (pi/pi), 2+2-cos(pi) and even holding a mirror up to the final ‘2’. There was also a neat 2⁰ /.2 from Paul Knutson…

Our Bonus Question, asking readers to identify the missing country, was more straightforward:

Korea – Ban Ki-Moon; Ghana – Kofi Annan; Egypt – Boutros Boutros-Ghali; Peru – Javier Peres de Cuellar; Austria – Kurt Waldheim

A great effort this week from: Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA; Ralf Ortmayr, senior pricing analyst, Toyo Tire Europe GmbH, Willich, Germany; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami, Japan. Well done!

Question 2: Missing letter

Find the missing letter in the following sequence:

B, _ S, V, T, SLC, N, L...

Answer: Like an Olympic ski run, some got there in record time, others trailed in a bit later, a few didn’t finish at all. A special mention – not for the first time – to David Mann, who spotted within minutes that this represented a list of locations for the Winter Olympics, with P for Pyeongchang, South Korea missing from the letter sequence.

Well done to: David Mann, manager rubber technology, SI Group, Béthune, France; Ian Brooker, HB Chemical Corp., Twinsburg, Ohio, USA; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Jon Cutler, materials development manager, Trelleborg Sealing Solutions Tewkesbury, UK; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Canada; Tom Bell, marketing & business services in elastomers, S & T Group LLC, Houston, Texas, USA; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami, Japan; Amparo Botella, Ismael Quesada SA, Spain; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA.

Question 1: Rubber ball

A rubber ball is dropped from a distance of nine metres from the floor, and continues to bounce. Each time it bounces back two thirds of the distance of the previous bounce. How far will the ball travel before it stops?

Answer: Not our toughest, but still a few  quite a few readers were off-the-mark. Well done to everyone here, who correctly replied 45 metres - or as Yuichi Sano explained 9/(1-2/3)x2-9: Amparo Botella, Ismael Quesada SA, Spain; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium; Michael Simpson, research & development engineer, Trelleborg AVS, Leicester, UK; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Canada; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami, Japan; Randa Tharwat, import manager, Nacita Automotive, Cairo, Egypt; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany;

FEBRUARY

This month's award goes to a reader who has been in or around pole position since we launched our Brainteaser competition. Congratulations to:

                                                   Industry consultant John Bowen our new Brainiac of the Month

Question 5: Average EV

An electric vehicle, with a mass of 600kg, starts from rest and accelerates to reach a velocity of 30 m/s in seven seconds. Assuming the motors and transmission are 100% efficient, approximately what is the average power transferred from the battery during this time?

Answer: Not sure we should have ended up five questions in February. Anyway, this one proved much trickier than expected, with only four of our top experts coming up with the correct answer 38.6 kW. As David Mann explained: kinetic energy gained = ½ mass (velocity)2 = 0.5 x 600 x 900 = 270000 Joule. Therefore, average energy output (power) = energy / time = 270000 / 7 = 38.6kW.

Extra well done, so, this week to: John Bowen, consultant, Bromsgrove, Worcestershire, UK; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Canada; David Mann, manager rubber technology, SI Group, Béthune, France; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA.

Question 4: Prime problem

How many prime numbers can you find between 1 and 100 that are simultaneously one greater than a multiple of four and one less than a multiple of five?

Answer: 29 and 89, or as Ian Brooker explained:  29-1=28 (4x7); 29+1=30 (5x6) and 89-1=88 (4x22);89+1=90 (5x18)

Well done to: Jon Cutler, materials development manager, Trelleborg Sealing Solutions, Tewkesbury, UK; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH  Obernburg, Germany; Ian. P. Jones, managing director, Continental, Contitech power transmission group, ContiTech United Kingdom Ltd, Wigan, UK; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; David Mann, manager rubber technology, SI Group,  Béthune, France; Aneta Skowron, kierownik zespo?u handlu, Zak?ady Chemiczne "Siarkopol" Tarnobrzeg sp. z o.o., Poland; Paul Knutson,  textile engineer, Timkin Belts, Springfield, Missouri, USA,  Magy Adib, import specialst and Sara Wagdy, import supervisor, Nacita, Cairo, Egypt; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Canada; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium; Ian Brooker, HB Chemical Corp., Twinsburg, Ohio, USA; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd. Hyogo, Japan.

Question 3: Missing number

Complete the sequence below:

2 + 3 = 8

3 + 7 = 27

4 + 5 = 32

5 + 8 = 60

6 + 7 = 72

7 + 8 = ?

Answer: There seems to be quite a few codebreakers among ERJ readers as this proved to be one of the most popular teasers in recent months. Well done to everyone who came up with the correct answer, 98: John Bowen, consultant, Bromsgrove, Worcestershire, UK; Amparo Botella, Ismael Quesada SA, Spain; Aneta Skowron, kierownik zespo?u handle, Zak?ady Chemiczne "Siarkopol" Tarnobrzeg sp. z o.o., Poland; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; David Mann, manager rubber technology, SI Group, Béthune, France; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA; Dimitri Aslanidis, business & technology development, AMS Forces, Belgium; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Canada; Kho Irani, Vistalon market development, speciality elastomers & butyl, ExxonMobil Chemicals, Springwoods Village Parkway Spring, Texas, USA;  Maxime Vandewiele, trading rubber, Sogescol, Switzerland; Michael Easton, sales and marketing director, Globus Group, Manchester, UK; Yehia Abd El Whab, Eldelta Tires;  Tomi Pekkola, sales director, Black Donuts Engineering Inc., Finland; Mahendra Modi, licensing & technology director, Goodyear Tire & Rubber Co., Houston, Texas, USA; Jon Cutler, materials development manager, Trelleborg Sealing Solutions Tewkesbury, UK; Sara Wagdy, import supervisor, Nacita Automotive, Cairo, Egypt; Randa Tharwat, import manager, Nacita Automotive. Downtown. Cairo, Egypt

Question 2: Near miss

Two autonomous vehicles are being trialled at different ends of a straight stretch of motorway. However, due to a computer malfunction, both test teams lose control and the vehicles enter a collision course at 65km apart. The north-bound car is traveling at 55km/hr and the south-bound car at 80km/hr. Luckily, the teams manage to stop both cars simultaneously, exactly two minutes before collision. What is the distance between the vehicles when they stop?

Answer: As Thierry Montcalm nicely explained, the cars were 4.5 km apart ((55km/h+80km/h)X(2 min)X(1/60 h/min). An extra mention also to Jose Padron who provided his own bonus answers, including; if they stop only a third of a second before collision; the distance between the two vehicles should be just 12.5 metres.

Anyway, well done to in order of reply to: David Mann, manager rubber technology, SI Group, Béthune, France; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA; Dejan (Dan) Andjelkovic, technical director – industrial solutions, The Hallstar Company, Bedford Park, Illinois, USA;  Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami, Japan; Amparo Botella, Ismael Quesada SA, Spain; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Ioan Masec, technician, rubber mill, Mitas a.s., Praha, ?zech Republic; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Canada.

Thanks for your patience during the scheduled maintenance holiday for our Brainiac supercomputer.

Question 1: Chance en-counter

There are 10 coloured counters in a box. If two counters are picked out at random, the probablity of them both being blue is 2/15. How many of the coloured counters in the box are blue? There was also a bonus Question: A technician wrote down a sequence of six two-digit numbers from a tire rotating on a test rig: Find the missing number.: 16, 06, 68, 88, _, 98.

Answer: Readers were in fine form: working out that there were 4 blue counters (x(x-1)/(9*10) = 2/15), with most also spotting that the sequence was 86, 87, 88, 89, 90, 91 – when the tire stopped spinning.

Well done to: David Mann, manager rubber technology, SI Group, Béthune, France; John Bowen, consultant, Bromsgrove, Worcestershire, UK; Amparo Botella, Ismael Quesada SA, Spain; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium; Thierry Montcalm, R&D chemist, Soucy Caoutchouc, Canada; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA; Ralf Ortmayr, senior pricing analyst, Toyo Tire Europe GmbH, Willich, Germany; Robert van Herwaarden, production director, AEGIR-Marine Group, The Netherlands: Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami, Japan.

JANUARY

Well done to all for a quick return to form after the holiday break. But, for his rapid-fire reply to tricky Question 2, there can only be one winner of this month's top title. Big congratulation to

                                   David Mann, our first Brainiac of the Month of 2018.

Question 4: Old timer

At a celebration marking a rubber trading company's 100th year, former chairman Mr. Tim remarked that his grandson was about as old in days as his son was in weeks. The grandson, the retired chairman added, was also as many months old as he was in years. Together, the three family members were 140 years old. How old was Mr Tim?

Answer: Mr Tim was 84 years old (his son 49 and grandson 7). Correct answers arrived in, in the following order, from: John Bowen, consultant, Bromsgrove, Worcestershire, UK; David Mann, manager rubber technology, SI Group, Béthune, France; Amparo Botella, Ismael Quesada SA, Spain; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH,Obernburg, Germany; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Fatima Bhatti, Polymer Access (Pvt) Ltd, Karachi, Pakistan; Ian Brooker, HB Chemical Corp., Twinsburg, Ohio, USA; Ralf Ortmayr, senior pricing analyst, Toyo Tire Europe GmbH, Willich, Germany. Well done.

Question 3: Old house

Mathematician Steve was musing that his house was built on 1 Jan,1978, and saw that if he added the first two digits (19) to the last two (78), the total was the same as the middle two digits (97). Assuming it is still standing, how old would Steve's house be when the year next had this same property?

Answer: Yes, let’s hope Steve’s house is well-built as the year would be 2307 - making the answer 329 years. Thanks also to Jose Padron for providing a ‘bonus answer’: this mathematical rule will be repeated each 110 years, before changing a millennium: 2417, 2527, 2637, 2747, 2857, 2967.

Well done to: Amparo Botella, Ismael Quesada SA, Spain; Stephen Fulton, R&D technology development manager, Umicore Specialty Materials Brugge NV, Brugge, Belgium; David Mann, manager rubber technology, SI Group, Béthune, France; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; Fatima Bhatti, Polymer Access (Pvt) Ltd, Karachi, Pakistan; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA.

Question 2: Missing letters

Fill in the gaps in the following letter-pairs:

D_, B_, G_, B_, G_, R_, J_

(To help, we added some of the letters during the week)

(Bonus question: What feature have the following six-letter words in common?: abhors, almost, bijoux, billow, chintz, effort?)

Answer: Initials of the names of US presidents DT, BO, GB, BC, GB, RR, JC - Donald Trump, Barack Obama, George Bush, Bill Clinton, George Bush, Ronald Reagan, Jimmy Carter - while the words in the Bonus question had their letters in alphabet order.

Extra well done to David Mann, manager rubber technology, SI Group, Béthune, France who came up both answers within minutes on Monday morning. He was followed soon after by John Bowen, consultant, Bromsgrove, Worcestershire, UK; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Jon Cutler, materials development manager, Trelleborg Sealing Solutions, Tewkesbury, UK. Well done also to Fatima Bhatti, Polymer Access (Pvt) Ltd, Karachi, Pakistan who answered our Bonus question straight away.

Question 1: Shared birthdays

For a company survey, HR executive Simon has established that birthdays in the workforce are spread equally over a 365-day year. Using a random selection process, how many employees does he need to select before the chance of two or more of them sharing a birthday (eg 2 January), is greater than 50%?

Answer: Firstly Happy New Year to everyone. This was fairly straightforward starter for 2018: to have more than a 50% chance of 2 people with the same birthdate in any year you need 23 people. Getting off on the right foot were: John Bowen, consultant, Bromsgrove, Worcestershire, UK; David Mann, manager rubber technology, SI Group, Béthune, France; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK.