Lateral Thinking · Ages 18+
Riddle #217
You're on a game show facing three closed doors: a car behind one, goats behind the other two. You pick door #1. The host, who knows what's behind every door, opens door #3 to reveal a goat, then offers you the choice to switch to door #2 or stay with door #1. To maximize your odds of winning the car, what should you do, and what are your odds?
You solved this one before
Open-ended riddle: think it through, then reveal the answer.
Answer: Switch to door #2 — doing so wins the car 2/3 of the time, versus only 1/3 if you stay.
The host's guaranteed reveal of a goat concentrates the original 2/3 chance that "the car is behind one of the other two doors" entirely onto the one door he didn't open. This is the classic Monty Hall problem.