# Consider the revised Coal Bank Hollow recycling problem discussed in section 5.5.4 of this chapter. We said that it is safest to assume the supply in a generalized network flow problem is capable of meeting the demand (until Solver proves

Consider the revised Coal Bank Hollow recycling problem discussed in section 5.5.4 of this chapter. We said that it is safest to assume the supply in a generalized network flow problem is capable of meeting the demand (until Solver proves otherwise).

a. Solve the problem in Figure (a) (and file Fig (a).xls on your data disk) assuming 80 tons of newspaper is available and that the supply is NOT adequate to meet the demand. How much of each of the raw recycling materials is used? How much demand for each product is met? What is the cost of this solution?

b. Solve the problem again assuming that the supply is adequate to meet the demand. How much of each of the raw recycling materials is used? How much demand for each product is met? What is the cost of this solution?

c. Which one is better? Why?

d. Suppose there are 55 tons of newspaper available. Figure (b) shows the least cost solution for distributing the supply in this case. In that solution, the demand for newsprint pulp and packaging pulp is met but we are almost 15 tons short on print stock pulp. How much can this shortage be reduced (without creating shortages of the other products) and how much extra would it cost to do so?

Figure (a)

Figure(b)