what is paul's service charge

Question

for a home computer repair paul charges an hourly rate plus a service charge. when he works 4 hours he charges $140.00 when he works 7 hours he charges $278.00. what is paul's service charge

Answer 1

c represents his service charge

h represents the number of hours

c + 4h = 140

c + 7h = 278

 

Can you solve for h then answer the question?