Consider the following set of activities. Immediate Predecessors Activity ABCDEFGHLIKL A. B A, B C,D. D E, F F F G, H H, I J, K I recommend developing a network for this project first. The time required to complete each activity is as follows. ABCDEFGHLIEL Activity Time (Days) 3 DIGNIT32545 1 Using the information above. 1) formulate a linear programming model to determine the length of the project above and 2) solve it using Excel. If this project is required to be finished in 21 days. Using the information below, 1) formulate and 2) solve a linear programming model to minimize the cost of crashing. Activity allowable crashing (Days) A B C DEFGHL I IKL J K L 1 2 2 1 2 0 2 3 2 2 1 2 Crashing Cost / Day $10 $15 $18 $20 $16 -- $5 $7 $30 $24 $20 $17 1 2 3 Decision Variables 4 Variable Names 5 Math Symbol 6 Variable Values 7 Acitivy Duration 8 9 Crashing Variables 10 Math Symbol 11 Variable Value 12 12 13 Max days to crash .. 14 15 16 17 18 19 20 21 22 23 25 24 First Predecessor 2nd Predecessor Xa 27 O.F. 28 Cost of Crashing 29 30 31 32 Ya = Xc YC = 5 2 18 Xd Yd = 3 D from B >= 1 20 Xe F Number of Days to Start Activity I where I = A, B,....L Xf Xg Xh = 2 number of days to reduce duration of Activity I where i=A,B,...L Ye Yf Yg Yh Yi E from D >= 2 G 16 = 0 0 H = G from F >= 4 = Xi 3 = 2 2 30 XJ Yj = J from H >= 5 2 24 Xk Yk = K from I >= 4 1 20 XI YL = L from K >= 5 LHS OP 2 RHS 17 N # of days to done d(duration) Done from L >= 0 OP2 RHS2 OP3 RHS3 1