Regal Metals manufactures steel lavatory partitions for commercial buildings. Once a week, orders are accumulated at the Toledo, Ohio plant (X = 460, Y = 720) for delivery to construction sites. The firm owns five trucks with a hauling capacity of 40,000 lb. For a particular week, the following deliveries are to be made:
The trucks are to be scheduled in such a way that all orders for the week are to be shipped at one time beginning no earlier than 7:00AM at Toledo, capacities of the trucks are not be exceeded, and all trucks are to be returned to the Toledo plant. Additional restrictions are that all deliveries are to be made between 7:00AM and 6:00PM, drivers are to take a 1-hour lunch break after 12 noon and an overnight (12 hour) break after 7:00PM, and the barrier to travel of the Great Lakes is to be respected. Average driving speed is 50 miles per hour, and the time for unloading at a stop is 30 minutes per stop. Road distances are estimated to be 21 percent higher than straight line, coordinate-computed distances. Driver and truck costs are $1.30 per mile. When not traveling, drivers are assigned duties at the plant.