Question 1152966
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<pre>

Let x = amount invested at 9%.

Then amount invested at 7% is (5000-x).


The total interest equation is


    0.07*(5000-x) + 0.09x = 390   dollars.


From the equation


    x = {{{(390-0.07*5000)/(0.09-0.07)}}} = 2000.


<U>ANSWER</U>.  Investments are $2000 at 9% and the rest,  5000-2000 = 3000 dollars at 7%.


<U>CHECK</U>.   0.09*2000 + 0.07*3000 = 390  dollars.   ! Precisely correct !
</pre>

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,  &nbsp;or if you want to see other similar problems solved by different methods, &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.