Look for a pattern #4

In each table, fill in the missing numbers or expressions:
(a)
1
2
3
4
5
8
10
?

3
6
9
12
?
?

?
48

(b)
1
2
3
4

5
9
12
?

3
5
7
9
?
?

?
37

(c)

1
2
3
4
5
8
?

1/2
1/6
1/12

1/20
?
?
1/110

We're still looking for patterns here. The new ingredient is that you should try to see how to relate the numbers on the top row of each table to those in the bottom row. Be alert for the pattern! As always, be sure to explain the work you did to arrive at your answers!