Variable Change/ Monty Hall Problem

Hey so everyones probably heard of this problem either from the movie 21 (you know where he has 3 doors to choose from and one door has a car... etc) or from studying for interviews.

Does anyone get this problem thoroughly? If so, can you explain it? Also, has anyone been asked it in a SA/FT interview?

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Best Response

You (probably) wont get the problem now. It's too well known/ too easy in the first place (caveat- i got one question that was so easy i thought it was a joke):

Basically, you have three paths. The car is at the end of one path.

You choose a path. At this point there is a 33% chance you choose the right one.

Someone points out which oen of the other paths is wrong (one of them has to be wrong, since there is only one right path).

Remember, there is a 33% chance you're on the right path. That means there's a 67% chance one of the paths you didn't choose was right. This holds true even after one of the paths you didn't choose is disqualified. This means the last path you didn't choose has a 67% chance of being the correct one, while the path you're on only has a 33% chance.

 

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