You aren't gonna let this thread die Mr. Slac,are you?
Anyway, its nice. I have one too.

We are given the following:
Two trains are traveling towards each other on the same track.
One train is traveling at 30 miles per hour, the other at 20 mph.

When the trains are 100 miles apart, a fly leaves one and flies
towards the other. When it reaches the other it immediately travels
back to the first. Upon returning, it immediately starts back to
the second, and so on, until the trains crash.

Question: When the trains crash, how far has the fly travelled,
if it flies continuously at 50 mph?


Note that when we say 'immediately' above, we mean that there was
no time whatever lost in turning around -- that there was an
instantaneous change of motion.