A pension fund manager decides to invest a total of at most $25 million in U.S. Treasury bonds paying 6% annual interest and in mutual funds paying 9% annual interest. He plans to invest at least $5 million in bonds and at least $10 million in mutual funds. Bonds have an initial fee of $100 per million dollars, while the fee for mutual funds is $200 per million. The fund manager is allowed to spend no more than $4000 on fees. How much should be invested in each to maximize annual interest? What is the maximum annual interest?
