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 hasan output of 100, 200, and 600 barrels of low-, medium-, andhigh-grade oil per day, respectively. The company wishes to produceat least 1000, 1400, and 3000 barrels of low-, medium-, andhigh-grade oil to fill an order. If it costs $400/day to operateRefinery I and $600/day to operate Refinery II, determine how manydays each refinery should be operated to meet the productionrequirements at minimum cost to the company.
| RefineryI | days |
| RefineryII | days |
What is the minimum cost?
$
