Question: PRODUCTION CONTROL An oil company operates two refineries in a certain city. Refinery I has an output of 200, 100, and 100 barrels of low-, medium-, and high-grade oil per day, respectively. Refinery II has an output of 100, 200, and 600 barrels of low-, medium-, and high-grade oil per day, respectively. The company wishes to produce at least 1000, 1400, and 3000 barrels of low-, medium-, and highgrade oil to fill an order. If it costs $200/day to operate refinery I and $300/day to operate refinery II, determine how many days each refinery should be operated in order to meet the production requirements at minimum cost to the company. What is the minimum cost?