Problem of the Week
Airport Traffic-------3/19/07-------
A woman arrives at an airport between 11 and 12 o'clock. She waits for her husband for 10 minutes and if he doesn't arrive, she hails a taxi. Her husband shows up at the airport at some time between 11 and 11:50. He waits for 20 minutes and if his wife hasn't shown up, he goes back home. What is the probability that the woman rides home with her husband?
(AoPS: and Beyond)