Intermidiate algebra
posted by jay .
a woman ivests in two bank accounts, one with a 3% percent interest and the other paying 9% simple interest per year.She puts twice as much in the lower account. Her annual interest is 7110. How much did she invest in each account?

higher account  x
lower account  2x
.09x + .03(2x) = 7110
.15x = 7110
x = 47400
$47400 at 9% and $94800 at 3%
check:
.09(47400) = 94800(.03) = indeed 7110