I don't know if I've posted this in the right place but I thought I'd give it a go anyway. 1. The problem statement, all variables and given/known data See Attatchment 2. Relevant equations 3. The attempt at a solution So for part a) max z:150X11+350X12+300X13+100X21+500X22+400X23 s.t. X11+X12+X13≤40 X21+X22+X23≤90 X11+X21≥30 X12+X22≥40 X13+X23≥60 For (b) eliminate first constraint and label constraints: u2,v1,v2,v3 Then solve for us and vs and i get u1=0 u2=100 v1=0 v2=400 and v3=300 Then c*12=50 so not optimal (c) Enter X12 into basis create loop etc. but that give new solution as X12=40, X21=30 and X23=60. But then when you go through us and vs again to test for optimality, you've got 5 variables to solve for and only four equations so I'm stuck. Help please!