(a) Use the NW corner rule to find an initial BFS, then solve using the transportation simplex method. Indicate your optimal objective function value.
(b) Suppose we increase s1 from 15 to 16, and d3 from 10 to 11. Show that even though an extra unit is being shipped, the total shipping cost actually decreases by $2. Explain why increasing both supply and demand has resulted in a decreased solution cost by relating this phenomenon to the dual variables associated with supply node 1 and demand node