(3 part answer) Carletta has 10500 dollars to invest.

(3 part answer) 

Carletta has 10500 dollars to invest. As her financial consultant, you recommend that she invest in Treasury Bills that yield 5%, Treasury Bonds that yield 6%, and corporate bonds that yield 7%. Carletta wants to have an annual income of 610 dollars, and the amount invested in corporate bonds must be half that invested in Treasury Bills. Find the amount she should place in each investment. 

Carletta should invest

____?_______ dollars in Treasury Bills, ______?_______ dollars in Treasury Bonds, and __________?_______ dollars in corporate bonds to attain 610 dollars annual income.