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How many people would need to be in a group to have a 50% chance that two people will have the exact same birth date (month and day)?

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23

A group of 40 has 90% chance two will share an exact birthday in the year.

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idk

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400

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The answer is a surprising 23 people. In a room with just 23 people, the odds are someone will have the exact same month and date birthday. Kinda surprising.
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Aw you didn't praise me "shady" hehe.
Show them how to do it ay ?
365/365 x 364/365 x 363/365 is chance 3 people WON'T share a birthday
When you do 23 people [using 23 fractions in that pattern] you get about 50%.
Each fraction drops by 1 on the top line cos one less day is available still that does NOT match anyone.
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Now this is good stuff. Thanks for your contribution.
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2

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