A pension fund manager decides to invest a total of at most ​$40 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 ​$15 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 ​$7000 on fees. How much should be invested in each to maximize annual​ interest? What is the maximum annual​ interest? \