work problem

Question

8. Two printing presses can turn out one day’s newspapers in
6 hours. The faster press can do the job, operating alone,
in 10 hours. How long would it take the slower press, operating
alone, to do the job?

Answer 1

Let faster press work rate = 1/10 of whole job per hour (alone).

let other press work rate = 1/p, i.e. by itself it would take p hours to do entire job.

Then entire job can be done in 6 hours: 6(1/10) + 6(1/p) = 1.

Solve for p.