The hiway trucking company hauls company freight in maricopa county, arizona. Hiway estimates the aggregate quarterly demand for next year at 5,000 , 7,500 , 9,500 , 5,000 ton miles. Trucking equipment owned by the company, rented trucks and subcontracting can be used to supply capacity to meet aggregate demands. source of capacity capacity of each square (ton-miles quarter) cost of capacity (Ton-mile) COMPANY TRUCKS: straight time 0-4000 $0.25 overtime 0-2,000 0.30 work force changes 0-1,000 0.35 Rented trucks (includes drivers and freight handlers) 0-3,000 $0.40 Subcontracting 0-5,000 $0.42

a. Formulate the aggregate planning problem in a linear formulation and define the decision variables. In other words,write each decision variable and expalin what one unit of the variable means.

b. Define the objective function and the aggregate demand constraint. Define also the straight time operation constraints, the overtime operation constraints, the operation of company trucks with work force-changes constraints, and the subcontracting constraints.

c. What is the aggregate plan?

d. Evaluate the plan?