ERJ Brainteaser: February 2019

Starting in Turkey and moving west across Europe, find the missing city in the following sequence:

Ankara, _, Oslo, Andorra la Vella.

Answer: These are the names (in English) of capital cities beginning and ending with the same letter. The missing city, so, was Warsaw.

Expertly well done to: John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Stephan Paischer, head of product management special products, Semperit AG Holding, Vienna, Austria; Andrew Knox, Rubbond International, Ohé en Laak, The Netherlands; David Mann, Polymer Business Development, France; Ramasubramanian P, L&T Rubber Processing Machinery, Larsen & Toubro Ltd, Tamil Nadu, India. A special mention also to Michele Girardi Scame Mastaf Spa, Suisio, Italy for his help in pointing out a slight blip with the question on Monday.

Bonus question: More soup

As we had two valid answers for Question 3, we ran this on into this week, asking readers to identify what came next in the ‘officially’ correct sequence ABC, BCE, CEH, EHM, _

Answer: HMU came next in the sequence, as David Mann explained: gaps of 5 and 8 according to the Fibonnaci series.

Well done to: John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; Stephan Paischer, head of product management special products, Semperit AG Holding, Vienna, Austria; Andrew Knox, Rubbond International, Ohé en Laak, The Netherlands; David Mann, Polymer Business Development, France; Ramasubramanian P, L&T Rubber Processing Machinery, Larsen & Toubro Ltd, Tamil Nadu, India; Amparo Botella, Ismael Quesada SA, Spain. A special mention also to Hans-Bernd Lüchtefeld of PHP Fibers GmbH in Germany, who came quite close with his answer (pictured across).

Find what comes next in the following sequence:

ABC, BCE, CEH, _

Answer: As sometimes happens, a valid, alternative answer has emerged for this week’s Brainteaser. So well done to the following readers who worked out the ‘officially’ correct sequence: ABC, BCE, CEH, EHM: John Droogan, advanced polymers and composites, MegaChem (UK) Ltd, Caldicot, Monmouthshire, UK; John Bowen, consultant, Bromsgrove, UK; Michael Easton, sales & marketing director, Globus Group, Manchester, UK; Michele Girardi, Scame Mastaf Spa, Suisio, Italy;

And, equally well done to readers who provided the alternative valid answer EHL: Amparo Botella, Ismael Quesada SA, Spain; Bharat B Sharma, Sr V.P. product development & technical service (elastomers), Reliance Industries Ltd, Vadodara Manufacturing Division, Petrochemicals, Vadodara, Gujarat, India; Thierry Montcalm, R&D and innovation manager, Soucy Techno, Canada; Ramasubramanian P, L&T Rubber Processing Machinery, Larsen & Toubro Ltd, Tamil Nadu, India; Varun Sureka, Hartex Rubber Pvt. Ltd, Hyderabad, India.

This sequence was explained concisely by Amparo Botella: ABC, BC(D)E, CE(FG)H, EH(IJK)L

A projectile is fired at a horizontal velocity of 150 metres/second. It hits a target at a horizontal distance of 30 metres. Assuming negligible air resistance effect, what is a) the flight time of the projectile? and b) its vertical displacement?

Answers: Well done to the following readers who answered part (a) correctly ie 0.2 seconds: John Bowen, consultant, Bromsgrove, UK; Thierry Montcalm, R&D and innovation manager, Soucy Techno, Canada; P. Ramasubramanian, Larsen & Toubro Ltd, Rubber Processing Machinery, Tamil Nadu, India: David Mann, Polymer Business Development, France; Olaf Mayer-Mader, Abteilung BA-M, product management and business development PA, Festo AG & Co. KG, Denkendorf, Germany.

And even more well done to those readers who answered the more tricky part (b) correctly ie 0.196 metres (0.2m also accepted): John Bowen; Thierry Montcalm and David Mann

John Bowen’s solution neatly shows how it’s done:

a] Flight time = 30/150 = 0.2 secs

b] Vertical displacement: we use s = ut + 1/2.f.tsqd = 0 [fired horizontally so no initial vertical component] + 1/2 * 9.8*0.2*0.2 [f = acceleration due to gravity, 9.8m/sec/sec] = 0.196 metres.

Fill in the missing cities in the following sequence:

Reykjavík, _, Oslo … Montevideo , _, Wellington.

Answer: Just two correct replies, so extra well done to: P Ramasubramanian, manager, marketing – mixer and LTKMPL products, rubber processing machinery, Larsen & Toubro Ltd, Vedal Village, Kanchipuram, Tamil Nadu, India; and Yuichi (Joe) Sano, Sumitomo Electric Industries Ltd, Itami, Japan. Our other Brainiacs really do need to get out more.

As P Ramasubramanian nicely explained: This is a sequence of national capital cities sorted by latitudes.  Northernmost national capital is Reykjavic (capital of Iceland @ 64.14 N) and the southernmost national capital is Wellington (capital of New Zealand @ -41.28 S).

So, the sequence is:

Reykjavic – capital of Iceland (64.14 N), Helsinki – capital of Finland (60.17 N), Oslo – capital of Norway (59.9 N) …  Montevideo – capital of Uruguay (34.88 S), Canberra – capital of Australia (35.3 S), Wellington – capital of New Zealand (41.28 S).