Question

What is the probability that at least two people have the same birthday in a room of twenty-five people?

Answer 1

This is a classic problem. It is nto easily solved directly. It's much simpler by calcualting, "What's the probability that no two people share a birthday?"

Yu may wish to think of it like this:

1) Line up everyone at the party.
2) Send the First person in line up to a blank calandar and have this person mark of the appropriate date. Obviously, the probability that it lands on someone else's birthday is zero (0).
3) Send the second person in line to mark off the appropriate date. The probability is 1/365 that the date is already taken. and 364/365 that it is not taken.

(Given some leeway for Leap Years)

4) Send the third person in line to mark off the appropriate date. The probability is 2/365 that the date is already taken. and 363/365 that it is not taken.

Continue on this way to the 25th person.

Answer 2

Better than 50%

Answer 3

thanks guys. so would it make sense that if i were to round to four decimal places, the answer would be 0.5687?

Answer 4

I haven't, or maybe can't work it out, but that sounds reasonable. I think in a room of 23 it is around .5

Answer 5

thank you so much for your help!

Answer 6

There is a lot of info on Google just search on "birthday probability"

Answer 7

You're welcome.