27. PC-Express is a computer retail store that sells desktops and laptops. The company earns $600 on each desktop computer it sells and $900 on each laptop. The computers PC-Express sells are actually manufactured by another company. This manufacturer has a special order to fill for another customer and cannot ship more than 80 desktops and 75 laptops to PC-Express next month. The employees at PC-Express must spend about 2 hours installing software and checking each desktop computer they sell. They spend roughly 3 hours to complete this process for laptop computers. They expect to have about 300 hours available for this purpose during the next month. The stores management is fairly certain that they can sell all the computers they order, but are unsure how many desktops and laptops they should order to

maximize profits.

a. Formulate an LP model for this problem.

b. Sketch the feasible region for this model.

c. Find the optimal solution to the problem by enumerating the corner points.