1) The model for the transportation problem consists of 18 decision variables, representing the number of barrels of wastes transported from each of the 6 plants to each of the 3 waste disposal sites:2) Because the transportation model is formulated as a linear programming model, it can be solved with Excel Solver. The spreadsheet solution is shown in the following table.3) If each of the plant and waste disposal sites is considered as intermediate shipping points, the transportation model becomes a transshipment model. The additional decision variables included in the revised model are4) The computer solution for the transshipment model is obtained using Excel Solver and the output is given below. For doing the analysis using Excel solver we assume the shipping cost per barrel for the decision variables , , , ,,,,, are assumed to be 100 in order to make sure that the variable representing that routes do not have a value in the optimal solution.5) The total transportation cost for the initial transportation model is obtained as $2822. The optimal routes and the corresponding units to be shipped if the units are shipping directly from each of the six plants to each of the three waste disposal sites are summarized in the following table.