talk show host problem or what they call it

[ming]

in the movie, they pretty much force the guy to join the team because of his answer to what i personally think of as a questionable math problem.
you have 3 boxes with one prize and 2 that cointains nothing. the show host shows one of the empty boxes, and asks you to make your choice. that leaves you with 2 boxes, out of which one contains a prize and the other one does not. now how can your chances of picking the right one NOT be 50/50?
i have discussed it with my math teacher but never gotten a satisfactory answer.

[Sonny]

See the thread below this one called Lecture Scene.

-Sonny-