A company makes three products, I, II, and III, at three different factories. At factory A, it can make 10 units of each product per day. At factory B, it can make 20 units of II and 20 units of III per day. At factory C, it can make 20 units of I, 20 units of II, and 10 units of III per day. The company has orders for 200 units of I, 500 units of II, and 300 units of III. If the daily costs are $2000 at A, $3000 at B, and $5000 at C, find the number of days that each factory should operate in order to fill the company's orders at minimum cost. Find the minimum cost.