A businessman and a mathematician are sitting next to each other on a long flight from Cebu to Sydney. The businessman leans over to the mathematician and asks if he would like to play a fun game. The mathematician ignores it as he just wants to take a nap. But the businessman keeps disturbing him so he politely rolls over to the window to catch a few winks. The businessman insists and explains that the game is real easy and a lot of fun. He explains. "I ask you a question, if you don't know the answer, you pay me a 5 dollars. Then in turn, you ask me a question, if I cannot answer, I'll give you 5 dollars."But the mathematician politely declines and goes back to sleep. The businessman now somewhat bored and agitated and said, "OK, you pay me 5 dollars if you do not know the answer, but if I cannot answer your question, I'll pay you 100 dollars. Shoot?This catches the mathematician's attention. Seeing there?s no end to this torment unless he plays, he agrees to the rules of the game. The businessman asks, "What is the distance from the earth to the moon?"The mathematician doesn't say a word. He reaches into his wallet, pulls out a 5 dollars and courteously hands it to the businessman. Now, it?s the mathematician's turn. He asks the businessman. "What goes up a hill with three legs and comes down with four?"The businessman looks up at him with a puzzled look. He takes out his laptop computer and searches all of his references. He taps into the airphone with his modem and searches the net and the Library of Congress. Frustrated, he sends e-mail to his co-workers for an answer, but to no avail.After an hour, he wakes the mathematician and hands him one clean 100 dollars. The mathematician takes the 100 dollars and turns away to try to get back to sleep.The businessman troubled and confused, shakes the mathematician and asks, "Well, what is the answer?"Without a word, the mathematician reaches into his wallet, pulls out a 5 dollars, hands it to the businessman and turn away to get back to sleep.