There are three doors.  Behind one of the doors is a brand new car.  Behind the other two doors are goats.  Don’t ask me why they’re goats.  They’re just always goats.

You’re asked to choose a door.  Let’s say you choose door number 1.

The host of the show opens a different door – a door that he knows contains a goat.  Let’s say it’s door number 3.

The host then asks if you would like to change your answer.  You now only have two doors to choose from: Door number 1, and door number 2.  Would you change your answer?

This problem is called the Monty Hall problem.

The reason I’m posting this is because Jeff Atwood just brought it up on his blog, Coding Horror.  Funny though, that I had seen the movie 21, and already knew the answer and the reason why.  Check out his article because he sheds a little light on some of the history surrounding this problem.

The best way to answer would be to change your door.  If you change your answer your probability of winning doubles.

Interested in a good explanation of the reason why?  Check the video…