Solution:
Let x = the amount invested at 11%
Then, 5900 - x = the amount invested at 6%
The total annual return from the two investments is $ 509.00
Therefore,
11 % of x + 6 % of 5900 - x = 509
[tex]\frac{11}{100} \times x + \frac{6}{100} \times (5900 - x) = 509\\\\Simplify\\\\0.11x + 0.06(5900 - x) = 509\\\\0.11x + 354 - 0.06x = 509\\\\0.05x = 509 - 354\\\\0.05x = 155\\\\Divide\ both\ sides\ by\ 0.05\\\\x = 3100[/tex]
Thus, $ 3100 is invested at 11 % interest
5900 - x = 5900 - 3100 = 2800
Thus, $ 2800 is invested at 6 % interest