Answer
She invested 7000 dollars at 8% interest.
She invested 5000 dollars at 6% interest.
Work Step by Step
Let X represent the amount of money invested at 8% interest.
At the end of the year, she received 8% $\times$ X = 0.08X
Since she invested 12,000 dollars in total, at 6% interest she invested 12,000 - X.
At the end of the year, she received 6% $\times$ (12000 - X) = 720 - 0.06X
The total yearly interest from both investments was 860 dollars, so we can set up the following equation:
0.08X + 720 - 0.06X = 860
0.02X = 140
Divide both sides by 0.02
X = 7000
She invested 7000 dollars at 8% interest.
She invested 12000 - 7000 = 5000 dollars at 6% interest.
