Apension fund manager decides to invest a total of at most $25 million in u. s. treasury bonds paying 5% annual interest and in mutual funds paying 7% 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?