1)
(n-2) girls and 2 boys
Treat the two boys as one 'entity' and hence arrange (n-1) entities. Then, arrange the two boys.
i.e. possible permutations = 2! * (n-1)!
2)
5 drummers, 5 singers, 10 total people
the total number of ways to arrange these people in a line is 10!
the number of ways in...