Posted by Maerika on .
An executive invests $24,000, some at 7% and some at 5% annual interest. If he receives an annual return of $1600, how much is invested at each rate?

Math 
MathMate,
Let amount invested at 7% be $x.
Amount invested at 5% = $(24000x)
x*0.07+(24000x)*0.05 = 1600
Solve for x.