Enigma 310: Jogging on
14 September 2015
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From New Scientist #1458, 30th May 1985 [link]
“Nick and I have taken up jogging”, said Tom. “We ran round a field starting at the gate and we believe that, for all practical purposes, each of us jogged at our own constant speed.”
“After we had completed some laps and a few yards, I overtook Nick. Although we were tired, we kept on going, until we finally met at the gate. By this time I had done four laps more than Nick.”
“How many laps did you do?” I asked.
“That’s interesting — by coincidence, the number of his laps and the number of my laps (completed), when we first met and when we finished, were all composite”.
I suggested a possible answer to my question, but he said, “We weren’t that energetic!”
This reply enabled me to work out the correct answer.
What is it?