Need help please

Question

A plumber charges a service call fee plus a price per hour to do the work. One job took 5 hours and cost $500, another job that took 3 hours to complete and cost $350.

What does the plumber charge for the service call fee and what is his price per hour?

Answer 1

f represents the sevice fee

p represents the per hour charge

f + 5p = 500

f + 3p = 350

Can you solve for p and answer?