Answer:
C(M) = 0.65*M + 22.55
Explanation:
We know that the cost to rent and drive for M miles is given by:
S(M) = 0.40*M + 17.75
And the insurance, also a function of M, is given by:
I(M) = 0.25*M + 4.80
We want to find the equation of the total cost for a rental that includes insurance.
This would be just the sum of the two above functions:
C(M) = S(M) + I(M)
C(M) = (0.40*M + 17.75) + (0.25*M + 4.80)
Now we just need to simplify this:
Taking M as a common factor, we get:
C(M) = (0.40 + 0.25)*M + 17.75 + 4.80
C(M) = 0.65*M + 22.55
Then the total cost equation, as a function of M, is given by:
C(M) = 0.65*M + 22.55