_Here's a neat problem I've heard from Christian Szegedy:_

N cars are moving in the same direction with different speeds on an infinite straight road. They can't pass eachother so clusters form. What's the expected number of clusters?

N cars are moving in the same direction with different speeds on an infinite straight road. They can't pass eachother so clusters form. What's the expected number of clusters?
 
_Feel free to discuss in the comment section. Don't forget to vote on Sunday!_