Example (Transportation Problem) A company has two plants producing a certain product that is to be shipped to three distribution centers. The unit production costs are the same at the two plants, and the shipping cost per unit is shown below. Distribution Center 1 2 3 Plant A $4 $6 $4 B $6 $5 $2 Shipments are made once per week. During each week, each plant produces at most 60 units and each distribution center needs at least 40 units. How many units should be shipped from each distribution center to each distribution center, so as to minimize cost? Spreadsheet Solution of the Transportation Problem Example Figure 5.1: Location of the canneries and warehouses for the P & T Co. problem. CANNERY 1 Bellingham WAREHOUSE 3 Rapid City CANNERY 2 Eugene WAREHOUSE 2 Salt Lake City WAREHOUSE 1 Sacramento WAREHOUSE 4 Albuquerque CANNERY 3 Albert Lea Figure 5.2: A spreadsheet formulation of the P & T Co. problem as a transportation problem, where rows 3-9 show the parameter table and rows 12-20 display the solution table after using the Excel Solver to obtain an optimal distribution plan. Both the formulas for the output cells and the specifications needed to set up the Solver are on the next slide. Figure 5.2: The formulas for the output cells and the specifications needed to set up the Solver. Figure 5.3: The network representation of the P & T Co. transportation problem shows all the data in Table 5.5 graphically. De ma nds Supplie s Destina tions Sourc es 464 (Be llingham) 75 S1 867 352 (E ugene) 125 S2 995 (Alber t Le a)100 S3 513 654 D1 80 (Sa cr amento) D2 65 (Sa lt La ke City) D3 70 (Rapid City) D4 85 (Albuquerque ) 416 690 791 682 685 388 Example (Assignment Problem) (Problem 5.22 in the book) The coach of a swim team needs to assign swimmers to a 200-yard medley relay team (four swimmers, each swims 50 yards of one of the four strokes). Since most of the best swimmers are very fast in more than one stroke, it is not clear which swimmer should be assigned to each of the four strokes. The five fastest swimmers and their best times (in seconds) they have achieved in each of the strokes (for 50 yards) are Backstroke Breaststroke Butterfly Freestyle Carl 37.7 43.4 33.3 29.2 Chris 32.9 33.1 28.5 26.4 David 33.8 42.2 38.9 29.6 Tony 37 34.7 30.4 28.5 Ken 35.4 41.8 33.6 31.1 How should the swimmers be assigned to make the fastest relay team? Spreadsheet Solution of the Assignment Problem Example Figure 5.18: The formulas for the output cells and the specifications needed to set up the Solver for the Sellmore Co. problem.