jack invested $4000 in two accounts. one pays simple interest at the rate of 5% and the other pays simple interest at the rate of 6%. if jack earned a total of $224 in interest in the first year, how much did he invest in each account?

Answer 1

He invested:

$X @ 5%.
$(4000-X) @ 6%.

.05x + 0.06(4000-x) = 224.
0. 05x - 0.06x + 240 = 224.
-0.01x = 224 - 240 = -16.
X = $1600.
4000-X = 4000-1600 = $2400.