Major differences between Simple and Dual method of solving LPP

Major differences between Simple and Dual method of solving LPP (Apr 2004)

The Simple method is used for solving maximization problem.  We convert all constraints into equalities by adding a slack variable in each resource (S1, S2, etc.) Then we prepare the simplex table. Basic variables in 1^st table are slack variables.

In Dual method, we convert minimization problem into maximization problem. Decision variables are represented by Y1, Y2, etc. Objective function of Primal becomes constraint RHS in Dual. Constraint RHS in Primal become objective function in Dual. All ≥ constraints get converted in ≤ constraints. Then we add a slack variable in each constraint. Slack variables are represented by r1, r2, etc.

In the optimal table, shadow prices of slack variables (r1, r2 etc.) of Dual represent quantity of decision variables (X1, X2 etc.) of Primal.