Question

An automotive repair center charges $45 for any part of the first hour of labor, and $25 for any part of each additional hour. Which of the following is a correct cost?
A. C(t) = 95 for 1 < x ≤ 2
B. C(t) = 95 for 2 < x ≤ 3
C. C(t) = 120 for 2 < x ≤ 3
D. C(t) = 120 for 4 < x ≤ 5

Answer 1

To answer this question, it is easier to make a list of the repair cost based on the hour of labor. The first hour is $45 then after that $25/hour. Then the list would look like 

0-1 h= $45
1-2h= $70     ($45 +1*$25)
2-3h= $95    ($45 +2*$25)
3-4h= $120   ($45 +3*$25)

Looking at the list, the answer should be
B. C(t) = 95 for 2 < x ≤ 3