Posted by Sarah Mae B. Oquindo on .
1. Investment. Part of $25,000 is invested at 10 percent, another part is invested at 12 percent, and a third part is invested at 16 percent. The total yearly income from these three investments is $3,200. Furthermore, the income from the 16 percent investment yields the same amount as the sum of the incomes from the other two investments. How much is invested at each rate?

math 
drwls,
Suppose x is invested at 10%, y is invested at 12% and z is invested at 16%. Here is what you know:
x + y + z = 25,000
0.10 x + 0.12 y + 0.16 z = 3200
0.16 z = 0.10 x + 0.12 y
You can immediatley write
2*(0.16 z) = 0.32z = 3200
So z = $10,000
Therefere x + y = $15,000.
You also know that
0.10x + 0.12 y = 1600
Now finish it. You have two equations in two unknowns left.