Question

PLEASE HELP I’M SO CONFUSED

A plumber charges a customer based on the number of hours worked. The cost can be determined by the function C(h) = 45h + 75 where h is the number of hours worked

a. What is the hourly rate of the plumber?

b. If the bill totaled $311.25, how many hours did the plumber work?

Answer 1

a. $45 an hour

b. 5.25 hours

Explanation:

a. The plumber charges $75 per job, so it is irrelevant to the number of hours they work. 45(h) is $45 multiplied by the number of hours they work.

b.

First, plug the numbers into the equation, the cost being C(h):

311.25 = 45(h) + 75

Next, subtract $75 as it is a set price that is always payed:

236.25 = 45(h)

Then, divide both sides by 45 to find how many hours were worked:

h = 5.25

Hours = $5.25