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Old 02-07-2011, 06:45 PM   #74
Rusty
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Quote:
Originally Posted by lawn psycho View Post
Come on, you can do better than that. Here's a simple one that is counterintuitive to people. What is the probability that two people share the same birthday (only needs to be the same month/day and can ignore year). Hint: Not as common as you would think.
The first person can have any birthday. That gives him 365 possible birthdays out of 365 days, so the probability of the first person having the "right" birthday is 365/365, or 100%.
The chance that the second person has the same birthday is 1/365. So the probability that both people have this birthday, you multiply their separate probabilities. (365/365) * (1/365) = 1/365, or about 0.27%.
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