Nash Auto has two plants, two warehouses, and three customers. The plants are in Detroit and Atlanta, the warehouses are in Denver and New York, and the customers are in Los Angeles, Chicago, and Philadelphia. Cars are produced at plants, then shipped to warehouses, and finally shipped to customers. Detroit can produce 800 cars per week, and Atlanta can produce 400 cars per week. Los Angeles requires 450 cars per week, Chicago requires 300, and Philadelphia requires 250. It costs $10,000 to produce a car at each plant. The costs of shipping a car between various cities are listed in the file P05_56.xlsx. Assume that during a week, at most 250 cars can be shipped from a warehouse to any particular city. Determine how to meet Nash's weekly demands at minimum cost.