The Weekend Edition Saturday Math Guy, Stanford professor Keith Devlin, has a problem. In fact, he has more than one... which he's happy to share with Scott Simon. What is the probability that in a ...

Alfredo has a PhD in Astrophysics and a Master's in Quantum Fields and Fundamental Forces from Imperial College London.View full profile Alfredo has a PhD in Astrophysics and a Master's in Quantum ...

Here's a fun brain teaser: How large does a random group of people have to be for there to be a 50% chance that at least two of the people will share a birthday? The answer is 23, which surprises many ...

Imagine you’re at a party. There are 23 people in the room, including you. Someone proposes a bet: “I bet at least two people here share the same birthday.” You do the mental math. With 365 days in a ...

You don't have to tell me that I suck at probability. I don't know why I always get confused and I never trust my answers. What to do next? How about I model the "how many graduates have their ...

If you are in a room with 22 other people, it’s more likely than not that two of them share a birthday. There was something strange about the recent Women's World Cup in Australia. If you were paying ...

Editor’s Note: Published in 1957, this article comes from Martin Gardner’s legendary Scientific American column Mathematical Games. Read more in our special digital issue, Fun and Games. A paradox is ...