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?
(In reply to Sit !! Stay !!
I wholly agree with Penny.
The "simultaneous" start invites variety of interpretations and without any refinements leaves the final location of Rex undefined.