Steinwelt Piano Manufactures Uprights and Consoles in Two Plants, Plant

Steinwelt Piano manufactures uprights and consoles in two plants, plant I and plant II. The output of plant I is at most 180 pianos/month, whereas the output of plant II is at most 150 pianos/month. These pianos are shipped to three warehouses that serve as distribution centers for the company. To fill current and projected orders, warehouse A requires a minimum of 120 pianos/month, warehouse B requires at least 90 pianos/month, and warehouse C requires at least 120 pianos/month. The shipping cost of each piano from plant I to warehouse A, warehouse B, and warehouse C is $60, $60, and $80, respectively, and the shipping cost of each piano from plant II to warehouse A, warehouse B, and warehouse C is $80, $70, and $50, respectively.
Use the method of this section to determine the shipping schedule that will enable Steinwelt to meet the warehouses' requirements while keeping the shipping costs to a minimum.
__________ pianos from plant I to warehouse A
__________ pianos from plant I to warehouse B
__________ pianos from plant I to warehouse C
__________ pianos from plant II to warehouse A
__________ pianos from plant II to warehouse B
__________ pianos from plant II to warehouse C