The charge to rent a trailer is $30 for up to 2 hours plus $9 per additional hour or portion of an

The charge to rent a trailer is $30 for up to 2 hours plus $9 per additional hour or portion of an hour. Find the cost to rent a trailer for 2.4 hours, 3 hours, and 8.5 hours.

Set up the cost function C(h), where h is the number of hours to rent the trailer. We have, for any hours greater than 2:
C(h) = 30 + 9(h - 2)

Simplified, we have:
C(h) = 9h - 18 + 30
C(h) = 9h + 12

The question asks for C(2.4), C(3), and C(8.5)

Find C(2.4)
C(2.4) = 9(2.4) + 12
C(2.4) = 21.6 + 12
C(2.4) = 33.6

Find C(3)
C(3) = 9(3) + 12
C(3) = 27 + 12
C(2.4) = 39

Find C(8.5)
C(8.5) = 9(8.5) + 12
C(8.5) = 76.5 + 12
C(8.5) = 88.5