In a roomful of 30 people, what is the probability that at least two people have the same birthday? Assume birthdays are uniformly distributed and there is no leap year complication.

Olpers Aug 26, 2018

#1**+3 **

In a roomful of 30 people, what is the probability that at least two people have the same birthday?

What is the prob that 30 people in a room **all have different birthdays**? (asssuming no one is born on 29th Feb)

365/365*(364/365)*(363/365) ...... [(366-30)]/365 = 0.2937

So the prob that 2 or more have the **same birthday** is 1-0.2937 = 0.7063 approximately.

Melody Aug 26, 2018

#1**+3 **

Best Answer

In a roomful of 30 people, what is the probability that at least two people have the same birthday?

What is the prob that 30 people in a room **all have different birthdays**? (asssuming no one is born on 29th Feb)

365/365*(364/365)*(363/365) ...... [(366-30)]/365 = 0.2937

So the prob that 2 or more have the **same birthday** is 1-0.2937 = 0.7063 approximately.

Melody Aug 26, 2018