Question 1116363
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<pre>
Let x be an amount invested at 6% (the lesser amount).

Then the amount invested at 9% is 2x, according to the condition.


Your equation to find x is


<U>interest</U> + <u>interest</U>   = <U>total interest</U>,    or


0.06x    + 0.09*(2x)  = 1440


0.06x + 0.18x = 1440  ====>  0.24x = 1440  ====>  x = {{{1440/0.24}}} = 6000.


<U>Answer</U>.  $6000 was invested at 6%.  $12000 was invested at 9%.


<U>Check</U>.   0.06*6000 + 0.09*12000 = 1440 dollars.   ! Correct !
</pre>

Solved.


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It is a typical and standard problem on investment.


To see many other similar solved problems on investment, &nbsp;look into the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/coordinate/lessons/Using-systems-of-equations-to-solve-problems-on-investment.lesson>Using systems of equations to solve problems on investment</A>

in this site.


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


Also, &nbsp;you have this free of charge online textbook in ALGEBRA-I in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>.


The referred lesson is the part of this online textbook under the topic &nbsp;"<U>Systems of two linear equations in two unknowns</U>".



Save the link to this online textbook together with its description


Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson


to your archive and use it when it is needed.