# Three Curtains

**URL:** <https://boards.straightdope.com/t/three-curtains/634061>\
**Category:** The Game Room\
**Created:** [September 8, 2012, 1:54am UTC](https://boards.straightdope.com/t/three-curtains/634061 "2012-09-08T01:54:34Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![rstrats](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@rstrats](https://boards.straightdope.com/u/rstrats)\
**Post date:** [September 8, 2012, 1:54am UTC](https://boards.straightdope.com/t/three-curtains/634061/1 "2012-09-08T01:54:34Z")

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You are a contestant on a game show. There are three curtains. Behind one of the curtains is a new car. You are asked to choose one of the curtains. Lets say that you choose curtain #1. The host of the show - who knows where the car is so as not to end the game prematurely - opens curtain #3 and of course there is no car behind it. The host now gives you a choice. You can stay with curtain #1 or you can change your choice to curtain #2. The question now is: would it be to your advantage to stay with curtain #1, or would it be to your advantage to change to curtain #2 or would there be no advantage either way?

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**Author:** ![zoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zoid/32/336_2.png) [@zoid](https://boards.straightdope.com/u/zoid)\
**Post date:** [September 8, 2012, 1:59am UTC](https://boards.straightdope.com/t/three-curtains/634061/2 "2012-09-08T01:59:17Z")

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It’s to your advantage to switch.  
We’ve done this a dozen times. Search for Monty Hall.

[http://boards.straightdope.com/sdmb/showthread.php?t=499621&highlight=monty+hall](http://boards.straightdope.com/sdmb/showthread.php?t=499621&highlight=monty+hall)

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**Author:** ![Mahaloth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mahaloth/32/1079_2.png) [@Mahaloth](https://boards.straightdope.com/u/Mahaloth)\
**Post date:** [September 8, 2012, 1:59am UTC](https://boards.straightdope.com/t/three-curtains/634061/3 "2012-09-08T01:59:21Z")

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Dude, that’s the Monty Hall problem and it is a very old Dope article.

[Monty Hall Problem](http://www.straightdope.com/columns/read/916/on-lets-make-a-deal-you-pick-door-1-monty-opens-door-2-no-prize-do-you-stay-with-door-1-or-switch-to-3)

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**Author:** ![rstrats](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@rstrats](https://boards.straightdope.com/u/rstrats)\
**Post date:** [September 8, 2012, 2:12am UTC](https://boards.straightdope.com/t/three-curtains/634061/4 "2012-09-08T02:12:05Z")

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Sorry - It won’t happen again.

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**Author:** ![Mosier](https://avatars.discourse-cdn.com/v4/letter/m/7ea924/32.png) [@Mosier](https://boards.straightdope.com/u/Mosier)\
**Post date:** [September 8, 2012, 2:28am UTC](https://boards.straightdope.com/t/three-curtains/634061/5 "2012-09-08T02:28:51Z")

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> [@rstrats](#):
>
> Sorry - It won’t happen again.

Don’t feel bad. It’s a pretty cool demonstration of how our first reactions to math and probability related questions are occasionally exactly wrong. Explaining WHY it’s better to switch from curtain 1 to curtain 2 leaves almost everyone going, “huh?” and eventually leads to “hmm…”

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**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\
**Post date:** [September 8, 2012, 5:28am UTC](https://boards.straightdope.com/t/three-curtains/634061/6 "2012-09-08T05:28:59Z")

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I stay with my original choice.

Sure there’s a 66% chance it’s in the other curtain, but what you’re forgetting is that there’s a 100% chance that I’m awesome and have therefore picked the right curtain to begin with.