I worked out the rest of the questions, but I am stuck on what to do at the end.

The problem reads:

Julie needs to hire a plumber. She is told that the cost of hiring the plumber, C , is a function of time spent on the job, t , in hours. The plumber charges a one time fee of $60 and an hourly rate of $50.

The first question said "Determine a function which describes the total cost of hiring the plumber as a function of time"

and I put "C=60 + 50X"

So, the question that I am stuck on says

Find the Value for C(0).

...I did this

C(0) = 60 + 50x

0 = 60 + 50x

-60 = 50x

-6/5 = X

...Is this right? I ... have no idea what I am s'posed to plug 0 into.

I also tried

C(0) = 60 + 50(0)

C=60.

...The other questions are like

question2) If plumber took 2 hours, how much did he make?

c=60+50(2)

c=160$

question3)5 hours?

c=60+50(5)

c=310$

question4)

What if Julie paid him 210$?

210=60+50x

x=3 hrs.