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 Happy Birthday (3) (Posted on 2006-06-09)
In Happy Birthday, the question was if there are N people in a room, what is the probability that there are at least two people in the room who share a birthday?

What if instead exactly two was required? If there are N people in a room, what is the probability that there are exactly two people in the room who share a birthday?

(Note: Assume leap year doesn't exist, and the birthdays are randomly distributed throughout the year.)

 No Solution Yet Submitted by Sir Percivale Rating: 4.0000 (3 votes)

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 re(5): thoughts | Comment 11 of 12 |
(In reply to re(4): thoughts by Bob Smith)

Kudos to Robby for seeing the way forward.

Adding a factor of n/2 to my formula brings it in agreement with Charlie's.

 Posted by Bob Smith on 2006-06-12 09:12:34

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