Question

In how many ways can four people sit next to each other in a movie theater row?

Answer 1

As far as we can tell is just a Permutation

how many ways to arrange 4 out of 4, where order matters,

$\bf _nP_r=\cfrac{n!}{(n-r)!}\qquad \qquad \qquad \qquad _4P_4=\cfrac{4!}{(4-4)!}\implies \cfrac{4!}{1}$

Answer 2

2 of the them have to seat in the front row and the two others in the back