Question

A man invests his savings in two accounts, one paying 6 percent and the other paying 10 percent simple interest per year. He puts twice as much in the lower-yielding account because it is less risky. His annual interest is 418 dollars. How much did he invest at each rate?

Answer 1

if he has $x at 10%, then

.06(2x) + .10x = 418
.12x + .10x = 418
.22x = 418
...