>>12982813There was a 2/3 chance you were wrong when you made your choice. One of the doors gets removed from the problem, meaning either your choice is right or the only remaining choice is right. Since it's 2/3 that your choice is wrong, it's only 1/3 that the remaining door is wrong, hence a 2/3 chance the remaining door is right. So switching gives you a 2/3 chance of being right.