OK, I don't have a calculator but the first person's birthday could be anyone of 365 days in the year (ignoring leapyear). The second person could have any of 364 days as his birthday without being the same as the first guys (364/365). The third guy could have any of 363 days as his birthday without being the same as EITHER of the first 2 guys (363/365)
So, you would multiply these fractions until the result was less than 50% (because this calculates the chances that the any 2 birthdays are NOT the same).
To figure out how many people it would take before the chances are >50% that someone matches YOUR birthday, you would do the same thing, except you would keep using 364/365.
Yes?
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