You invested $25,000 in two accounts paying 6% and 7% annual interest, respectively. If the total interest earned for the year was $1720, how much was invested at each rate?

Answer 1

.07x + .06(25000-x) = 1720

expand, combine like terms, solve for x

.07x -.06x = 1720 -.06(25000)

.01x = 1720 - 1500 = 220

x = 220/.01 = $22,000 invested at 7%

$3,000 invested at 6%

check the answers

1720/22000 = 6.88%= average rate of return on both investments

7-6.88 = 0.12

6.88-6 = 0.88

88/12 = 22/3 = 7 1/3

you invested 7 1/3 times as much at 7% as at 6%

22/3 = 7 1/3

.07(22) +.06(3) = 154 + .18 = 1.72 = $1,720 interest on both investments