9 people drive into a parking lot, 4 are boys and 5 are girls.
They decide to park in a straight row of 9 spaces.
If none of the girls park next to each other, how many different parking arrangements are there?
If the girls are non-adjacent, there is ONE arrangement of the genders: .
Then the five girls can be arranged in: . ways.
The four boys can be arranged in: . ways.
Therefore, there are: .