All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Probability
Happy Birthday (3) (Posted on 2006-06-09) Difficulty: 3 of 5
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)

Comments: ( Back to comment list | You must be logged in to post comments.)
re(3): thoughts | Comment 5 of 13 |
(In reply to re(2): thoughts by Bob Smith)

Why is it that it is the nth person that shares a birthday with someone else?  Why not for example, the 10th person out of 30 matches the 15th out of the 30 people?
  Posted by Charlie on 2006-06-09 14:57:45

Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (10)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information