(this is a question my sister is trying to figure out and it says not birthdate but birthday) it also says assume there are 365 days in a year. may be a trick question but maybe not.
2007-01-21 10:33:15 · 19 answers · asked by farmbball 1 in Education & Reference ➔ Trivia
at least 2
2007-01-22 14:25:05 · answer #1 · answered by Anonymous · 0⤊ 0⤋
As you increase the number the odds go up but it will never be certain until you reach 366. At around 30 you can be pretty sure.
In any group of 23 people, the odds of at least two people having the same birthday is about 50%
You can have 365 people in a room all with different birthdays. As soon as you add the next one he has to match someone. (365 day year assumed)
2007-01-21 10:37:50 · answer #2 · answered by Barkley Hound 7 · 1⤊ 0⤋
60!!!
Math wise it is actually 60 for a 99% chance. It's tricky to explain the phenomenon in a way that feels intuitive. You can consider the fact that forty people can be paired up in 780 unique ways, and it follows that there would be a good chance that at least one of those pairs would share a birthday.
If there was one person in the room 365(or 366) possible birthdays
2 People in a room and there are 133 ,225 combinations and 365 ways in which they could have the same birthday.
Three people 48 ,627 ,125 possible combinations and 398,945 possibilities two people have the same birthday (or .8 percent) so for and so on!!!
2007-01-21 10:53:19 · answer #3 · answered by asmidsk@verizon.net 3 · 0⤊ 1⤋
First guy or woman walks into the room. He has a birthday. provide him a risk of a million, expressed as 365/365. 2nd guy or woman walks in. risk that his birthday isn't the comparable by way of fact the 1st guy or woman = 364/365. third guy or woman walks in, prob that his birthday isn't the comparable as first 2 = 363/364 An so on. here is what you get: 365/365 X 364/365 X 363/364 and so on. yet wait! you get an entire slew of cancellations, and you finally end up with: n/365 If n = 183, n/365 = .501 i could say you like 182 people.
2016-12-16 10:07:40 · answer #4 · answered by ? 4 · 0⤊ 0⤋
two,
to find two people in a room that have the same birthday you would , have to have 366 people to gaurantee it (assuming 365 days in a year)
but in order to have two people in a room share a birthday you only need two people in the room that have the same birthday
I think it makes sense if you think about it
2007-01-21 10:57:55 · answer #5 · answered by Anonymous · 2⤊ 0⤋
366... it's the Pigeonhole principle!
Pretend you have a house with 9 rooms. now you get 9 people to get inside. YOU want ONE room to have TWO people inside. but you cant force it. BUT if you get in to the house ONE more person you'll have that for sure! that's just like with the days, 365 days a year, but you can't force them... all you need is one more person (366) and you've got it!
see the source>>>
2007-01-21 10:49:28 · answer #6 · answered by Jack D 2 · 1⤊ 0⤋
2
that's all you have to have for 2 to share a birthday. everytime there are 2 people in the room, they won't share a birthday. but you don't need more than 2 people in the room in order for 2 to share a birthday.
2007-01-21 10:44:28 · answer #7 · answered by Anonymous · 0⤊ 1⤋
Statisically it is I think 22 to 24 people. I forget, I read this in Reader's Digest in 1987/1988.
I have tested it and it seems to be true. Take this many people in a room then they will be have the say birth month and birth day, but not birth year.
I found this on the net.
http://en.wikipedia.org/wiki/Birthday_paradox
2007-01-21 10:47:04 · answer #8 · answered by Mexico Traveler 3 · 0⤊ 1⤋
Only two people would need to be in the same room for a room to contain two people sharing the same birthday.
2007-01-21 10:36:43 · answer #9 · answered by Erika B 2 · 1⤊ 1⤋
Any two people could share the same birthday. Statistically speaking that isn't very likely though.
2007-01-21 12:02:24 · answer #10 · answered by istitch2 6 · 0⤊ 1⤋