Answer: 128 pieces of candy for all the cookies.
This needs a graph to solve
The relation ship is:
Cost per mile = Total cost / miles
P = C / m
2 out of 5 chance that you will attests get 3
D is a notation for differential. There is a d2 in your formula because in the numerator there are two differentials. The formula is thus the second derivative of a function with respect to two variables.