Question

a man invested a total of $3,000 in two investments. he made a profit of 3% on the first investment and 4% on the second investment. if his total profit was $107, what was the amount of each investment?

Answer 1

Let the amount that the man placed in the first investment be $x$. Then, the amount that he placed in the second investment has to be $\ 3000 - x$. Using those as the investment amounts, the total profit is given by adding the two separate profits as shown:

$.03x + .04(\ 3000 - x) = \ 107$

We can now solve for x:

$.03x + .04(\ 3000 - x) = \ 107$
$.03x + (\ 120 - .04x) = \ 107$
$\ 120 - .01x = \ 107$
$.01x = \ 13$
$x = \ 1300$

Thus,

First investment: $x = \bf \ 1300$
Second investment: $\ 3000 - x = \ 3000 - \ 1300 = \bf \ 1700$