By dcb on Mar 01, 2005
Don't be fooled by the apparent simplicity. You've been warned :-)
Monty tells you that behind the three curtains are hidden two booby prizes and one desirable prize. Since you won the game show's challenge, you get to pick! You figure you've got a ~33% chance of winning, so you randomly pick a curtain and cross your fingers. Vanna's twin sister walks over to the curtain of your choice and is about to reveal your prize. Your heart is racing. Then Monty stops her and asks if you're sure about your choice. In fact, he'll help you out! He tells Anna to open one of the other curtains. That one contains a goat! Now, asks Monty, do you want Anna to open your original curtain, or do you want to switch? What should you do? Does it matter?
In case you give up, here is the solution: