Monty Hall Problem

Today in my beginning Math class (I have to take it to graduate and needed an easy A... but basically it's just pure torture and I'm constantly bored) we discussed the Monty Hall problem. It goes as follows:

Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1 [but the door is not opened], and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?

So what do you think the answer is?

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