The Birthday Problem

The ‘Birthday Problem’ is a famous mathematical exercise:

How many people need to be in a room to reach probability that two of them have the same birthday?

One would typically assume that it would take far more than it does.

How many people do you think it takes for the probability that two of them share a birthday to reach 50% ?

Each of them has a chance to match every other person in the room…

It is only 23.