b. In calculating the profit contribution per unit, management doesn’t deduct labour costs because they are considered fixed for the upcoming planning period. However, suppose that overtime can be scheduled in some of the departments. Which departments would you recommend scheduling for overtime? How much would you be willing to pay per hour of overtime in each department?

c. Suppose that ten, six and eight hours of overtime may be scheduled in departments A, B and C, respectively. The cost per hour of overtime is E18 in department A, E22.50 in department B and E12 in department C. Formulate a linear programming model that can be used to determine the optimal production quantities if overtime is made available. What are the optimal production quantities, and what is the revised total contribution to profit? How much overtime do you recommend using in each department? What is the increase in the total contribution to profit if overtime is used?