Question 160766
Amount invested at 3%=x
Amount invested at 4%=18,000-x

Convert % into decimal format 3%=.03 4%=.04
The equation is as follows


.03x+.04(18,000-x)=$650


Use the distributive property

.03+720-.04x=650

Subtract 720 from both sides

add the two x terms

-.01x=-70

Divide both terms by -.01

x=$7000 invested at 3%

$18,000-$7,000=$11,000 invested at 4%

Let's double check our answer by calculating the interest generated by each portion and determining whether this amount equals the amount designated in the problem.


.03(7000)+.04(11000)=210+440=650

650=650