Answer
We invested 880 dollars at 4% interest.
We invested 1420 dollars at 6% interest.
Work Step by Step
Let X represent the amount invested at 4%.
The remainder, which is 2300 - X, will be invested at 6%.
From the first investment we earn 4% $\times$ X = 0.04X.
From the second investment we earn .06 $\times$ (2300 - X) =
138 - 0.06X.
We know that the interest earned by the 6% investment is 50 dollars more than the interest earned by the 4% investment, so we set up the following equation:
0.04X = 138 - 0.06X - 50
0.04X = 88 - 0.06X
0.1X = 88
Divide both sides by 0.1:
X = 880
We invested 880 dollars at 4% interest.
We invested 2300 - 880 = 1420 dollars at 6% interest.
