min f (x1, X2, ..., X6) M cixi + bixi + ai i=1 Subject To 6 6 Xi d; x2 - 750 = 0 i=1 i=1 min Xi EXEXi max 9" 'Z'T = 1A where 1 2 3 4 5 6 ai 240 200 220 200 220 190 bi 7 10 8.50 11 10.50 12 Ci 0.007 0.0095 0.009 0.009 0.008 0.0075 d; 0.0001 0.0003 0.0001 0.0002 0.0002 0.0001 rmin 100 50 80 50 50 50 pmax 500 200 300 150 200 120