Monty Hall Paradox

A game show has a prize hidden behind one of three doors coloured red, blue and green. The contestant chooses a door. The host, Monty Hall, then reveals the contents behind one of the other two doors and asks if they want to reconsider. Should the contestant switch or stay with their original choice?

Monty Hall was an American game show host. Each week the final contestant was given a crack at the major prize - a car. Assume the host knows which door has the car and never reveals what lies behind that door.

Use this applet to explore which strategy (stay or switch) is better and by how much. There are two game options given in this applet, you can choose to Play once or Play 50 times, which simulates 50 games given selected strategy.