=l. Can the shadow prices in the sensitivity report be validly used to determine the effect if Lydia were to change her maximum number of hours available to work per week from 20 to 25? If so, what would be the increase in the total profit?

m. Repeat part l if, in addition to the change for Lydia, David also were to change his maximum number of hours available to work per week from 40 to 35.

n. Use graphical analysis to verify your answer in part m.