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94    CHAPTER 3 LINEAR PROGRAMMING: SENSITIVITY ANALYSIS AND INTERPRETATION OF SOLUTION


                                    Figure 3.3 Effect of a Ten-Unit Change in the Right-Hand Side of the Cutting And
                                    Dyeing Constraint

                                                 D
                                              800
                                                               Objective Function Line



                                              600       C & D  10S + 9D = 7711.75  New Feasible Region
                                            Number of Deluxe Bags  400  I & P  (  S = 527.50 )
                                                                        Includes This Shaded Area
                                                                                  Optimal
                                                                                  Solution
                                                                                 D = 270.75





                                              200                                      0.7S + D = 640




                                                                                       F
                                                 0         200         400        600         800   S
                                                                 Number of Standard Bags




                                     That is, allowing a marginal (one unit) change in the constraint. We can now solve
                                     Equations. 3.7 and 3.6 to find the new optimal solution which is:

                                                                         S ¼ 538:75
                                                                         D ¼ 253:875
                                                            Profit contribution ¼ $7672:375
                                     Confirming that if we increase the cutting and dyeing constraint by one hour then
                                     profit contribution increases by $4.375. However, we can now undertake the same
                                     analysis on the other constraints, again seeing how a marginal increase in the right-
                                     hand side of a constraint changes the value of the objective function. If we look at a
                                     marginal change in the finishing constraint we have:
                                                                   0:7S þ 1D ¼ 630

                                                                1S þ 0:6667D ¼ 709
                                     which gives a new solution of:
                                                                         S ¼ 541:875
                                                                         D ¼ 250:6875

                                                            Profit contribution ¼ 7674:9375
                                     In the case of the finishing constraint, there is an increase in profit contribution of
                                     $6.9375 for a marginal increase in finishing hours. But what about the other two





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