Tire designer Simon has a very specific ritual for climbing up the steps to his office. First he climbs up to the middle step and thinks about a new design for 1 minute. Then he climbs up 8 steps and waits until he hears his colleagues chatting. Then he walks down 12 steps and quickly takes one step up. After a short rest, he walks up the remaining steps three at a time which only takes him 9 paces. How many steps are there?
Answer: 49, although those who answered 48 could be correct, as pointed out by some readers. Well done to Andrew Knox, Rubbond International, Ohé en Laak, The Netherlands; John D Burrows, textile consultant, France; John Bowen, consultant, Bromsgrove, UK; Paul Knutson, textile engineer, Timken Belts, Springfield, Missouri, USA; Fariha Rashid, marketing analyst, Kraton Polymers LLC , Houston, Texas; Jose Padron, material development specialist, Waterville TG Inc., Waterville, Québec, Canada; Ricardo Azcarate; Ramasubramanian P, manager, marketing – mixer and LTKMPL products, rubber processing machinery, Larsen & Toubro Ltd, Vedal Village, Kanchipuram, Tamil Nadu, India; Hans-Bernd Lüchtefeld, market research & communication manager, PHP Fibers GmbH, Obernburg, Germany; France Veillette, chef environnement, Usine de Joliette, Bridgestone Canada Inc., Canada;
If M = middle step, then top step is M+8-12+1+(9*3)= M+24. So there are 24 steps up from the middle, and 24 steps down from the middle, total 48 steps.
For the calculation, the middle step doesn’t count. There is no middle step on any odd number of steps, only on even numbers of steps.