If you’re thinking about studying maths at Imperial, you might be wondering what kind of problems first year studenst are supposed to solve in the tutorials. Last term I was a graduate teaching assistant (GTA) for a course Probability and Statistics I. Let’s see an example of a question posed by the lecturer, prof. Emma McCoy.

*Imagine that n people, including yourself and a friend, are seated at random in a row of n chairs. What is the probability that you sit next to your friend?*

This problem is easier than you think, especially after following the lectures. I’ll explain how to tackle this problem here.