What will be the monthly cost? What is C in terms of minutes of call time ?

Question

A pre-paid cell phone company charges $17.75 as a monthly access fee and $0.12 per minute of calling time.

Express the monthly cost  in terms of minutes of call time.     

What will the monthly cost be if you make 285 minutes of calls this month?  $

Answer 1

Let X = # of minutes

C = 0.12X + 17.75

C = 0.12(285) + 17.75

C = 34.20 + 17.75

C = $51.95

Answer 2

C = 17.75 + 0.12minutes

C = 17.75 + 0.12 * 285 = 51.95