Question
In group of three friends what is the probability that at least two have the same birthday?
Answers
Reiny
The first friend will have the birthday on some given day, doesn't matter when.
The prob that the second friend will have a different birthday = 364/365
the prob that the third friend will have a birthday from the other two = 363/365
prob that all three have different birthdays
= 1(364/365)(363/365)
So prob that somebody has the same birthday
= 1 - the above
= appr .0082
The prob that the second friend will have a different birthday = 364/365
the prob that the third friend will have a birthday from the other two = 363/365
prob that all three have different birthdays
= 1(364/365)(363/365)
So prob that somebody has the same birthday
= 1 - the above
= appr .0082