12.4-6. Speedy Delivery provides two-day delivery service of large parcels across the United States. Each morning at each col lection center, the parcels that have arrived overnight are loaded onto several trucks for delivery throughot heea. Since the competitive battlefield in this business is speed of delivery, the parcels are divided among the trucks according to their geo graphical destinations to minimize the average time needed to make the deliveries. On this particular morning, the dispatcher for the Blue River Valley Collection Center Sharon Lofton is hard at work. Her three drivers will be arriving in less than an hour to make the day’s de- liveries. There are nine parcels to be delivered, all at locations many miles apart. As usual. Sharon has losded these locations into her computer. She is using her company’s special software package, a decision support system called Dispatcher. The first thing Dis- patcher does is use these locations to generate a considerable num- ber of attractive possible routes for the individual delivery trucks. These routes are shown in the following table (where the numbers in each column indicate the onder of the deliveries), along with the estimated time required to traverse the route.