Question 1094914
Mr. Wilson invested money in two accounts. His total investment was $20,000. If one account pays 6% interest and the other pays 8% interest, how much does he have in each account if he earned a total of $1,380 in interest in 1 year? 
<pre>Let the 6%-investment amount be S
Then the 8% investment amount = 20,000 - S
We then get: .06S + .08(20,000 - S) = 1,380
.06S + 1,600 - .08S = 1,380
.06S - .08S = 1,380 - 1,600
- .02S = - 220
S, or 6%-investment amount = {{{highlight_green(matrix(1,3, (- 220)/(- .02), "=", "$11,000"))}}}
Amount invested at 8%: {{{highlight_green(matrix(1,3, "$20,000 - $11,000", "=", "$9,000"))}}}
That's all!! Nothing COMPLEX and/or CONFUSING!
P.S. I could've also used 2 variables: 1 for the 6% and another for the 8%.