The Interstate Truck Rental firm has accumulated extra trucks at three of its truck leasing outlets, as shown in the following table:

                                  

The firm also has four outlets with shortages of rental trucks, as follows:

                                  

The firm wants to transfer trucks from those outlets with extras to those with shortages at the minimum total cost. The following costs of transporting these trucks from city to city have been determined:

                                   

Solve this problem by using the computer.