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Richard von Mises: 2 puzzles worth knowing

2 puzzles from Richard von Mises, each explained in a minute and credited to the original work. Free on Savvy.

• The shared birthday bet

  How many people do you need in a room before it's more likely than not that two of them share a birthday?

  — Richard von Mises, Über Aufteilungs- und Besetzungswahrscheinlichkeiten (the classic 'birthday problem')

• In a room of just 23 people, there's better-than-even odds two share a birthday

  It sounds impossible: 23 people, out of 365 possible birthdays, yet the chance two of them share one already tips past 50%. The trick is that you're not checking one person against…

  — Richard von Mises, Uber Aufteilungs- und Besetzungswahrscheinlichkeiten

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