SOLUTION: Rachel invested $9000 in money market funds, part at 6% and the rest at 4.5% annual interest. after one year, she earned $ 480.75 in interest. How much was invested at each rate?

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Question 1151867: Rachel invested $9000 in money market funds, part at 6% and the rest at 4.5% annual interest. after one year, she earned $ 480.75 in interest. How much was invested at each rate?
Answer by ikleyn(52776)   (Show Source): You can put this solution on YOUR website!
.

x dollars invested at 6% and the rest, (9000-x) dollars invested at 4.5%.


The total interest is the sum of partial interest.


In the equation form it is


    0.06x + 0.045*(9000-x) = 480.75  dollars.


From the equation,  


    x =  = 5050  dollars.


ANSWER.  $5050 invested at 6%  and the rest,  9000-5050 = 3950  dollars invested at 4.5%.


CHECK.   0.06*5050 + 0.045*3950 = 480.75 dollars.   ! Precisely correct !

Solved.

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Every day we solve 3 - 5 similar problems at this forum.

It is a standard and typical problem on investments.

If you need more details,  or if you want to see other similar problems solved by different methods,  look into the lesson
    - Using systems of equations to solve problems on investment
in this site.

You will find there different approaches  (using one equation or a system of two equations in two unknowns),  as well as
different methods of solution to the equations  (Substitution,  Elimination).

Also,  you have this free of charge online textbook in ALGEBRA-I in this site
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The referred lesson is the part of this online textbook under the topic  "Systems of two linear equations in two unknowns".


Save the link to this online textbook together with its description

Free of charge online textbook in ALGEBRA-I
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to your archive and use it when it is needed.


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