Question 4: (30 points) (This question can be solved in 20 minutes easily) Consider the following original LP model. The standard form of this model is given below. Min Z-2X1 - 2X2 - X3+3X4 s.t. 2X1 + X2 + X4 < 20 -X1 + 2X2 + X3 <60 X1, X2, X3, X420 Min z-2x1 - 2X2 - X3 + 3X4 S.I. 2X1 + X2 + X4+ SI = 20 -X1 + 2X2 + X3 + S2 = 60 X1, X2, X3, X4, S1, S20 The following Simplex Table shows the optimal solution of the above model. Basic X1 X2 X3 X4 S1 S2 RHS z 0 0 -3 0 - 1 -60 X2 2 1 0 1 1 0 20 X3 -5 0 1 -2 1 20 Assume that the constraint “X3 - 3X4 <10" is added to the above model. Update the above optimal Simplex Table and find the new optimal solution by the Dual Simplex Algorithm. Write your conclusion such as "optimal solution", "unbounded solution" or "infeasible solution". Page 3 Page 3