1) p=# of paper clips, (p+5)/4
2) w=wages, 3w+18
3) a=# of apples, (a-8)/5=32
1 and 3 are a little ambiguous; they can be interpreted in other ways. I'll leave them as they are unless you have any questions.
I would have written 1) as follows:5 more than the number of paper clips, divided into 4 groups.
I would have written 3) as follows:8 less than the number of apples, divided into 5 groups, is 32.