Paul is able to grade p essays every half hour, and Sarah is able to grade s essays every hour. If Paul and Sarah work together grading essays for h hours, then in terms of p, s, and h, how many essays will they grade?

Indicate all such amounts.

1. p + s / h
2. 2p + s / h
3. h(p + s)
4. 2h(p + s)
5. h(2p + s)
6. h(p + 2s)
7. 2hp + hs