She should invest $30000 in the 9% fund and $10000 in the 13% fund.
<u><em>Explanation</em></u>
Suppose, the amount of investment at 9% rate is dollar.
As the total amount of investment is $40000 , so the investment at 13% rate will be:
So, the amount of earnings per year from 9% fund dollar
and the amount of earnings per year from 13% fund dollar.
Given that, the <u>total earnings per year is $4000</u>. So the equation will be......
So, the amount of investment at 9% fund is $30000 and the amount of investment at 13% fund = ($40000- $30000)= $10000