Question

In a race in which six automobiles are entered, how many ways can the first 4 finishers come in?

Answer 1

The order matters.

`k` objects can be chosen out of
`n` objects, when the order matters, in
`P(n,k)=(n!)/((n-k)!)` ways.

So the answer is
`P(6,4)=(6!)/(2!)=3\cdot4\cdot5\cdot6=360` ways.