One ran faster than the other, and they were seen to pass at a spot
720 yards from the baker’s shop.
Each stopped ten minutes at his destination and then started on the return journey, when it was found that they passed each other at a spot 400 yards from the butcher’s.
How far apart are the two tradesmen’s shops?
Of course each boy went at a uniform pace throughout.
Source: Henry Dudeney’s Canterbury Puzzles.