if an investor invest a total of $1900.00 and one earned 4% and the other 2% and his total profit is $66, how much did he invest in both funds?
amount invested at 4% ---- x
amount invested at 2% --- 1900 - x
solve for x :
.04x + .02(1900-x) = 66
(I suggest multiplying each of the three terms by 100 to get rid of those decimals)