> The problem being: Two trains are 60 miles apart and approaching each > other at 30 miles per hour. There is a fly flying between the > cowcatchers of each train, at 60 miles per hour, back and forth, turning > around immediately. What is the total distance covered by the fly > (relative to the ground, NOT taking the motion in opposite directions to > cancel) until the trains hit?
I've heard that one too, but with the additional detail that this was the story as told by Martin Gardner in one of his columns. I heard that the real problem was a lot harder, but that MG told a simplified version in the context of explaining the fly problem.
The problem you mention certainly strikes me as much too simple to have the ring of truth, since anyone could sum -that- series in their head in a few seconds!