Answer:
D. 80
Explanation:
We have the following function :
(I)
Where
is the monthly fee for after - school care and preschool.
Where
represents the number of hours spent in after - school care.
We know that the total monthly bill for one child was $750 ⇒

Using (I) we will find the value of the hours ''
'' that verifies the expression ⇒
⇒

We find that the value of the hours ''
'' is 80 hours.
The total number of hours the child spent in after - school care is D. 80