For the P & T Co$.$ problem described in Sec. $9\mathrm{.}1,$ suppose

that there is a $10$ percent discount in the shipping cost for all

truckloads beyond the first $40$ for each combination of cannery and

warehouse. Draw figures like Figs. $13\mathrm{.}3$ and $13\mathrm{.}4,$ showing the marginal

cost and total cost for shipments of truckloads of peas from

cannery $1$ to warehouse $1.$ Then describe the overall nonlinear programming

model for this problem.