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) = 100 - 4p?; 15ps4 a. Find the average rate of change of 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 20 boxes per dollar. (Type an integer or a decimal.) b. Find the instantaneous rate of change of demand when the price is $2. boxes per dollar. The instantaneous rate of change of demand when the price is $2 is (Type an integer or a decimal.)