Question 1113470
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<pre>
Let x = the amount invested at 4%.

Then the amount invested at 6% was (15000-x).



Your equation is THIS


<U>interest</U> + <U>interest</U>       = <U>total interest</U>


0.04x    + 0.06*(15000-x) = 760


0.04x + 0.06*15000 - 0.06x = 760


-0.02x = 760 - 0.06*15000 = -140  ====>  x = {{{(-140)/(-0.02)}}} = 7000.


<U>Answer</U>.  $7000 was invested at 4%;   the rest  $15000 - $7000 = $8000 was invested at 6%.


<U>Check</U>.   7000*0.04 + 8000*0.06 = 760.  ! 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.