Question 1139017
Figure out the probability that NONE of the five people have the same birthday, then subtract this result from 1.
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Probability than NONE of the five people have the same birthday:
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365/365 * 364/365 * 363/365 * 362/365 * 361/365 = 0.9729
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Probability that at least two people have the same birthday:
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1 - 0.9729 = 0.0271, or 2.71%.  (That's about a 1 in 37 chance.)