Question

Four friends are going to sit together in a roller-coaster car that has 4 seats. In how many different arrangements can they sit?

Answer 1

4 people can go in the first seat, then there are 3 left to pick for the next, then 2 left to pick for the last, then one for the final one. So there are 4 x 3 x 2 x 1 choices.

We can also say this is '4 factorial' or 4!