What is the probability that in a group of 30 people of at least one pair having the same birthday?

Question

Please also indicate the method of calculation.

Answer 1

bout 50%

yu duit it bakwards

start with 2 peepl...chans em DONT hav same birthdae=364/365

with 3 peepl, its 6/365

with 4, 12/365

around 30 peepl, bout 50% nun hav same birthdae=50% chans em du

Answer 2

Judging by the 365 days, that MIGHT be 30 divided by 730 days = 0,0410958904.  It WOULD be extra rare for that to happen.  The rarity would make the chnace reven more rare.  It depends on the rarity.