A company has nine executives who drive to work There are ni

A company has nine executives who drive to work. There are nine adjacent parking spaces reserved just for them and each executive may park in any untaken space. If six executives don\'t show up to work one day, in how many different ordered ways can the three other executives park in the nine spaces?

Solution

As order matters, we use permutations.

There are 9P3 = 9!/(9-3)! = 504 ways. [ANSWER]