Here's a good puzzle, sure stumps me: ( borrowed from cartalk.com)
RAY: You're one of a hundred people standing in line to get onto an airplane
that has 100 seats. There's a seat for every person who's in line, and each of
you has a boarding pass for your assigned a seat. The first person to walk onto
the plane drops his boarding pass and, instead of picking it up, decides, "I'm
just going to sit anyplace." He takes a seat at random.
Now, every other passenger will take either his assigned seat or, if that seat
is taken, that passenger will take any seat at random.
TOM: I've been on that flight!
RAY: Because you are such a kind, generous, and accommodating person, you are
the last passenger to walk onto the plane. Obviously, there's going to be one
seat left, because everyone else is sitting in his correct seat, or not.
The question is: What are the chances that you get to sit in your assigned seat?