Science & TechMental model
Three doors, one car: why switching doubles your odds.
A car sits behind one of three doors. You pick one; the host, who knows where the car is, opens another door showing a goat and offers a switch. Your first pick wins with probability 1/3, so 2/3 sat on the other two doors. The host eliminated one of those, so the remaining door carries the full 2/3.
Useful: When someone with knowledge eliminates options, the probabilities shift, in game shows and in business alike.
Source: en.wikipedia.org