Extra Exercise: Transhipment Problem (Ragsdale Q 5.17) A furniture manufacturer has warehouses in cities represented by nodes 1, 2, and 3 in the following figure. The values on the arc indicate the per unit shipping costs required to transport living room suites between the various cities. The supply of living room suites at each warehouse is indicated by the negative number next to nodes 1, 2 and 3. The demand for living room suites is indicated by the positive number next to the remaining nodes. 120 30 $20 -10 $30 $10 $50 $30 $20 a. Identify the supply, demand and transhipment nodes in this problem. b. Use Solver to determine the least costly shipping plan for this