A boy, a girl and a dog are standing together on a long, straight road. Simultaneously, they all start walking in the same direction: The boy at 4 mph, the girl at 3 mph, and the dog trots back and forth between them at 10 mph. Assume all reversals of direction instantaneous.

In one hour, where is the dog and in which direction is he facing?

Working backwards, if the boy was catching up the girl and the dog started somewhere between them, it wouldn't matter who he ran to first as they'd all end up together (at the start).

Posted by Jils on 2004-01-26 08:55:19