Edsel Motors produces cars in Detroit and Dallas. The Detroit plant can produce up to 8500 cars, and the Dallas plant can produce up to 4000 cars. Producing a car costs $2000 in Detroit and $1800 in Dallas. Cars must be shipped to 12 cities. The costs of shipping a car from each plant to each city and the city requirements are given in the file P05_57.xlsx. At most 1000 cars can be sent from a given plant to a given city. Determine how to minimize the cost of meeting all demands.