My degree's in maths so I don't need to google the answer

You switch. Because, when you took your choice, you had a 1/3 chance of being right and a 2/3 chance of being wrong. After the goat is revealed if you were right before (1/3 chance) you will be wrong now, and if you were wrong before (2/3 chance) you will be right now. The revelation of the goat does not affect the decision you already took or the chances of that decision having been right or wrong.

Posted By: Old Man, Nov 2, 16:14:38