A food company buys butter from a dairy cooperative and distributes and sells it to restaurants. The next three months have estimated demands of 3,000, 7,000, and 5,000 pounds. The estimated purchase costs for months 1, 2, and 3 are $1,000 per thousand pounds (month 1), $1,200 per thousand pounds (month 2), and $900 per thousand pounds (month 3). The storage costs are $100 per thousand pounds (month 1), $110 per thousand pounds (month 2), and $115 per thousand pounds (month 3). Assume no inventories are desired at the end of month 3, and there are no beginning inventories in month 1. Solve this problem using DP to minimize total purchase plus storage costs.