This is an interesting paradox on conditional probability.Supposing you were in a game show and the host shows you there doors;1,2and3.Behind one of these doors is a car.You pick a door at random,say 1.Before the host opens door 1,he says ‘let me open another door an show you that it does not contain the car’,just to add suspense.He then opens door 3 and shows that it does not contain the car.He then gives you the option to stay with door 1 or swap to door 2.What should you do?The most logical answer is that the probability of the car being behind door 1 is equal to the probability of it being behind door 2,which is 1/2.Wrong!By swapping to door 2,you actually double your chances of winning.