A quiz master asks a contestant to choose one of three doors to open. Behind one, he tells him, is a brand new Rolls Royce. Behind the other two are nanny goats. The contestant gets to keep whatever’s behind the door he chooses.
The contestant chooses one of the doors – let us say A.
Before opening the door, the quiz master – who, of course, knows what’s behind each door – then says that as he’s taken a liking to the contestant he’s going to give him another chance. He then opens one of the other doors – let us say C – to reveal a nanny goat. He then gives the contestant the option of sticking with his original choice, or instead choosing door B.
Q: What should the contestant do to maximise his chances of winning the Roller?
