Acrosonic manufactures a model g loudspeaker system in plants i and ii. the output at plant i is at most 800/month, and the output at plant ii is at most 600/month. model g loudspeaker systems are also shipped to the three warehouses—a, b, and c—whose minimum monthly requirements are 500, 400, and 400 systems, respectively. shipping costs from plant i to warehouse a, warehouse b, and warehouse c are $16, $20, and $22 per loudspeaker system, respectively, and the shipping costs from plant ii to each of these warehouses are $18, $16, and $14, respectively. what shipping schedule will enable acrosonic to meet the requirements of the warehouses while keeping its shipping costs to a minimum?