The most amazing math problem. Even for non-nerds...

Hello good people,

today I want to give you a short introduction to my favorite math problem of all time, the birthday paradoxon.

Problem

Given a room of X people and the question is how likely is it that at least 2 of these people have the same birthday? We assume that there are 365 possible days per year ( don't consider leap year)

The fun

This post is not about the mathamatical proof. Just take a guess (Don't scroll).
How high is the probabilty for 70 people in the room?

Solution

The probabilty is 99.9%.

Image Source: here

And that is a result that can be proofen mathamaticaly and also we tested it in our class room. The professor asked us ( we were about 65 people in the classroom) to say out loud our birthday and as soon as someone has the same birthday we should raise our hands. After 10 people, the first hand went up... And back then I had idea how this is working. (As short hint: You have to consider the opposite event that noone has has the same birthday and this rised very fast). After the professor gave us the proof we understood it mostly but still it drives me crazy....It is called

paradoxon

for a reason.

Hope you liked this small course to the world of math and