BruceZ is right. Here's how it works:


Let's say that you don't change your mind. The probability that you pick the door with the car behind is 1/3. So if you don't change your mind you will win the car 1 out of 3 times.


Now, let's say that you change your mind every time. The probability that you picked the door with the car behind is still 1/3. Let's say the car is behind door #1:


1) You pick door 1 (Quizmaster opens door 2 or 3)You switch = No car

2) You pick door 2 (Quizmaster opens door 3)You switch = Win the car

3) You pick door 3 (Quizmaster opens door 2) You switch = Win the car


The correct answer is to change your mind and switch. The strange thing is, that 4/5 people that you give this riddle to, will stick to their intuition and hang on to the door they picked first.


Has anyone got any ideas on how to use this at the pokertable? How about you BruceZ?


Yours


Mik