Suppose customers in a hardware store are willing to buy N(p) boxes of nails at p dollars per box, as given by the following function.
N(P) = 80 - 4p^2 ; 1 <= p <= 4.
Find the average rate of change in the number of boxes of nails that customers are willing to buy (demand) for a change in price from $2 to $3.
The average rate of change of demand for a change in price from $2 to $3 is ___ boxes per dollar.
(Type an integer or a decimal.)
I know the answer (-20) but I am not sure how to get it. Can you help?