* There are 3 doors. You pick one.
* The odds of “the door you picked” are 1/3. The odds of “**not** the door you picked” are 2/3.
* The host opens one door, then gives you a chance to change your pick. *Nothing has changed about the odds* – it’s still either 1/3 “the door you picked”, or 2/3 “**not** the door you picked”.
* Do you want to stick with 1/3 “the door you picked”, or change to 2/3 “**not** the door you picked”?
If you still don’t get it, this may help:
* Pretend the host gives you a chance to change your choice – not to another door, but to “*both* of these other doors you didn’t pick”. You’d *obviously* change your pick, right? Because then you get 2 doors instead of 1. Which would make it a 2/3 chance to win. Which is what happens if you change your pick.
Latest Answers