6. (9 pints). Consider the minimum cost flow problem below, where the b, values are given by the nodes. the values are given by the ares, and the finite u, values are given in the parentheses by the arcs. a) Formulate and solve a spreadsheet model for this problem. b) Include a network flow solution that shows your solution. c) Formulate the linear programming model for this problem. [50] [-70) (4 = 40) A D [0] 4 3 C 1 5 5 E B (n=40) 1-60] [80] 6. (9 pints). Consider the minimum cost flow problem below, where the b, values are given by the nodes. the values are given by the ares, and the finite u, values are given in the parentheses by the arcs. a) Formulate and solve a spreadsheet model for this problem. b) Include a network flow solution that shows your solution. c) Formulate the linear programming model for this problem. [50] [-70) (4 = 40) A D [0] 4 3 C 1 5 5 E B (n=40) 1-60] [80]