Answer:
7 girls can go in the first place, 6 in the second, etc.
7! ways is the number of ways to arrange the girls.
likewise the boys can be arranged in 7! ways
The total number of ways becomes 7! * 7!
7! * 7! = 25,401 600 ways
1.534
2.168
3.230
4.408
5.78
6.642
7.3
81016
9.1900
10.8 times (40 plus 5)
225 miles / 45 miles/hr = 5hr