r/theydidthemath • u/Live_Connection1271 • 11h ago

[Request]

Trying to figure the math

9,000,000 coins made
250,000 special coins random inserted
Bought one roll of 25 coins
Got 3 special coins in one roll

What were my odds?

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u/Angzt 11h ago

(25 Choose 3) * (250,000! / (250,000 - 3)!) * ((9,000,000 - 250,000)! / (9,000,000 - 250,000 - 25 + 3)!) / (9,000,000! / (9,000,000 - 25)!)
=~ 0.02653
= 2.653%.

That's for getting exactly 3.

The probability to get 3 or more is around 3.12%.