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Old 08-26-2005, 03:23 PM
Jordan Olsommer Jordan Olsommer is offline
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Join Date: May 2005
Posts: 792
Default Re: Jackpot Jay\'s Prop Bet

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can you explain the logic behind this bet, why its a good or bad one?

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I think the poster might have the details of the bet wrong, because by my calculations you'd need 87 people to have a 51% chance of one of them being born the day before, the day after, or the day of your birthday.

Since it's these three days that qualify, the odds of a random person being born within one day of your birthday are 3/365, so the odds of a random person not being born within one day are 362/365. (362/365)^87 ~= .49, so you'd have a 51% chance that someone in that group of 87 was born within that three-day period.

However this does sound similar to a bet of "Pick 22 people at random and I'll bet you even money that two of them have the same birthday", which is a bad bet to take (good bet for the person proposing it), since the odds of that happening are approximately 51%
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