The Birthday Problem: Shared Birthdays in a Room
You are at a party and wondering about birthday coincidences.
**Part 1:** There are $N \leq 365$ people in the room. What is the probability that at least two of them share the same birthday? Assume birthdays are uniformly distributed across 365 days and independent.
**Part 2:** Now focus on yourself. Given $N$ people in the room (including you), what is the probability that at least one other person shares your birthday?
Open the full interactive solver, hints, and worked solution →