did you know that if you have 31 people in a room odds are good that 2 will have the same birth date?

Question

if you want to read about it you can go to the link below....or you can look at the chart below the link....it breaks it down as to the % if you have 10 people together up to 366 which is the only way to gurantee 100% you only need 23 people to have a 50 50 chance of that happening....with 31 you have a better then 70% chance of that happening....

http://en.wikipedia.org/wiki/Birthday_paradox

n p(n)
10 12%
20 41%
23 50.7%
30 70%
50 97%
100 99.99996%
200 99.999999999999999999999999998%
300 (1 − 7×10−73) × 100%
350 (1 − 3×10−131) × 100%
366 100%

Answer 1

♥ I didnt know that. I learned something new today. Thanx! :-)

♥ I'm almost 20 and I've only met one person with the same birthdate as me... and that was just recently when I started college. My admissions rep had the same bday as me. (November 4)

Answer 2

I don't think so. I've been in many rooms with more than 30 people that have had no one with the same date of birth. Now, I believe someone could have the same NUMBER date but in different months. However, in order for that to work, you'd have to take into consideration that the number of children born isn't some equal number in every month. There are more children born in the month of Sept. than in any other month of the year. It's a higher chance that two will have a birthday IN Sept.

Answer 3

In high school I had two other people in one of my classes with the same birthday as me. June 17th.

It has nothing to do with there being 365 days. Its because there is 31 days is the most in a single month.

Answer 4

Yes, when I first went to school(30 or so pupils) there was another one with the same birthday and she was christened the same day too! She was always annoyed because I got there first both times. She and her friend were horrible to me.
I thought it was great that someone was born the same day as me.

Answer 5

Well, it depends what your definition of good odds are. If I considered 1/365 good odds, then having two people in a room would give me good odds. 31 is just where the odds become significant.

Answer 6

That is so cool and true, in a class of 29 students my best friend's b-day was the day after mine, close enough for 29

Answer 7

interesting
8/7 here

Answer 8

How can that be when there are 365 days in a year?

Answer 9

Cool I didn't know that! I love learning odd things like that.

Answer 10

That's interesting