Character Puzzles - General Questions

Find the missing number:

9   6   54
5   3   15
2   1   ?

Find the missing number:

6   4   24
7   1   7
9   2   ?

Find the missing number:

3   1   3
3   2   6
2   1   ?

Find the missing number:

3   2   5
5   4   9
7   6   ?

Find the missing number:

6   5   41
9   4   85
8   4   ?