Solve. Use interval notation to express the range.
-Parts for an automobile repair cost $609. The mechanic charges $29 per hour. If you receive an estimate for at least $783 and at most $870 for fixing the car, what is the time interval that the mechanic will be working on the job?
A) [6, 9]
B) [1, 9]
C) [1, 6]
D) [27, 30]

Question

Quizplus · Accepted Answer

The total cost is given by the equation $Total\ Cost = 609 + 29h$, where $h$ is the number of hours. For the estimate to be at least $783, we set $609 + 29h \geq 783$, solving for $h$ gives $h \geq 6$. For the estimate to be at most $870, we set $609 + 29h \leq 870$, solving for $h$ gives $h \leq 9$. Therefore, the interval is $[6, 9]$.

Solve. Use Interval Notation to Express the Range