# Probability that a deck of cards is tampered

**URL:** <https://boards.straightdope.com/t/probability-that-a-deck-of-cards-is-tampered/946559>\
**Category:** Factual Questions\
**Created:** [July 15, 2021, 1:30pm UTC](https://boards.straightdope.com/t/probability-that-a-deck-of-cards-is-tampered/946559 "2021-07-15T13:30:41Z")\
**Posts on this page:** 1\
**Showing post:** 9

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**Author:** ![DMC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dmc/32/18049_2.png) [@DMC](https://boards.straightdope.com/u/DMC)\
**Post date:** [July 15, 2021, 2:16pm UTC](https://boards.straightdope.com/t/probability-that-a-deck-of-cards-is-tampered/946559/9 "2021-07-15T14:16:28Z")

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If you have 52 cards, 25 are red, 27 are black, nothing else identifying about them other than color, you won’t know that it’s been tampered with until you draw the 27th black card. So you’re really asking for the odds that the nth draw exposes the 27th black card, unless I’m missing something.

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