Why You Should Always Switch Doors

In this famous probability puzzle, switching your choice after a door is opened doubles your chances of winning. Most people wrongly assume it makes no difference, but swapping is mathematically superior.

When you first pick a door, you have a one-in-three chance of being right. However, once the host reveals a losing door, the remaining unopened door effectively absorbs the higher probability of the initial choice you didn't make. This counterintuitive result is so baffling that even professional mathematicians once wrote in to argue it was wrong. It remains a perfect example of how our intuition often fails when dealing with conditional probability.