Say that you're on a game show with a chance to win a car.
There are three doors. Behind one of the doors, is the new car.
The host asks you to pick a door.
You do and point to it.
The host walks up to one of the doors you didn't pick and opens it. Behind that door is a pile of sand.
He asks if you want to change your choice from the two doors left.
Should you change your choice to the other door?