Bunuel wrote:

Mr. Rabner rents a car for d days. He pays m dollars per day for each of the first 7 days, and half that rate for each additional day. Find the total charge if d > 7.

(A) m + 2m(d - 7)

(B) m + m/2*(d - 7)

(C) 7m + m/2*(d - 7)

(D) 7m + md/2

(E) 7m + 2md

We can assume the number of days = 9, so d = 9

So for first 7 days, charge = 7 * m = 7m

For next 2 days, charge = 2 * m/2 = m

So total charge = 7m + m = 8m

So if we substitute d=9 in the correct option, our answer should be '8m'.

A) put d=9, m + 2m*2 = 4m

B) put d=9, m + m/2 *2 = 2m

C) put d=9, 7m + m/2 *2 =

8mD) put d=9, 7m + m* 9/2 = 11.5m

E) put d=9, 7m + 2m*9 = 25m

Thus

correct answer is C