Logic Puzzle 4

It's time to prove your Spock-like levels of logic.

of 2

I want to ride my bicycle…

Imagine a big park. Now imagine four cyclists being all irritatingly healthy and wholesome, cycling round and round in four separate circular paths. Each path is a third of a mile in circumference.

If they start at the same time, at the positions shown above, and if they're going at 6, 9, 12, and 15 mph respectively, how many times will they simultaneously return to the starting spots during a 20 minute workout?
I want to ride my bicycle…

Each circuit is a third of a mile, and 20 minutes is a third of an hour. That means they each travel that third of a mile 6, 9, 12 and 15 times. The largest number these are all divisible by is 3 – they therefore return to their starting positions 3 times, at the same time. Sorry if your brain now hurts.

I want to ride my bicycle…