4 votes 4 votes From a group of 30 students, what is the probability that at least two of them have birthday on the same day? Probability probability birthday + – hacker16 asked Jan 6, 2018 hacker16 578 views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply gauravkc commented Jan 6, 2018 i edited by gauravkc Jan 6, 2018 reply Follow Share It's 1 - 365Pn / 365n Where n is number of people. https://en.wikipedia.org/wiki/Birthday_problem 2 votes 2 votes hacker16 commented Jan 6, 2018 reply Follow Share thanks! @gauravkc 0 votes 0 votes Anu007 commented Jan 6, 2018 reply Follow Share 1 - every one have bday on different day = 1- $\left ( \frac{365 \times 364\times 363\times 362\times .....\times (365-29)}{365^{30}} \right )$ 2 votes 2 votes Anu007 commented Jan 6, 2018 reply Follow Share gaurav you copy half part only. formula for different day. 0 votes 0 votes gauravkc commented Jan 6, 2018 reply Follow Share Thanks :) 1 votes 1 votes Please log in or register to add a comment.