Birthday ProblemYou are currentlybrowsing as guest. Click here to log in 

If you have two people in a room, the probability that they share a birthday is really, really small. On the other hand, once there are 400 people in a room it's absolutely certain that some two of them will share a birthday. So as you add people to the room, the probability of a shared birthday, any shared birthday, goes from nearly zero right up to 1.
The probability that at least one pair share a birthday = 1  p If there are 23 or more (randomly chosen) people in a group then there is a more than even chance that two will share a birthday


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