SOLUTION: Amy invests $1500 in one account and $1900 in an account paying 3 % higher interest. At the end of one year she had earned $261 in interest. At what rates did she invest?
1500 i
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1500 i
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Question 1129650: Amy invests $1500 in one account and $1900 in an account paying 3 % higher interest. At the end of one year she had earned $261 in interest. At what rates did she invest?
1500 invested at -
1900 invested at- Found 2 solutions by Boreal, greenestamps:Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! interest for 1500 is x
interest for 1900 is x+3
1500*x/100=15x
1900*(x+3)/100=19x+57
that sum is 261
34x=204
x=6% for $1500=$90
X+3 is 9% for $1900=$171
Here is a solution using some logical reasoning and some mental arithmetic, instead of formal algebra.
First consider the "extra" 3% that is earned on the $1900 investment. The amount of interest there is .03($1900) = $57.
The remaining amount of interest is $261-$57 = $204. That is the amount of interest on the whole investment of $3400. Since we have accounted for the interest from the extra 3% on the second investment, that $204 interest is now all at the lower rate.
= 6%
The $1500 was invested at 6%; the $1900 was invested at 6%+3% = 9%.
