document.write( "Question 1133271: Larry Mitchell invested part of his $ 32,000 advance at 4% annual simple interest and the rest at 7% annual simple interest. If his total yearly interest from both accounts was $1,670​, find the amount invested at each rate. \n" ); document.write( "
Algebra.Com's Answer #750453 by ikleyn(52781)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "Each day we solve  2-3-4  similar problems at this forum.\r
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\n" ); document.write( "\n" ); document.write( "Therefore,  I will give here only shortest version of the solution,  referring for more complete solutions/explanations to the lesson\r
\n" ); document.write( "\n" ); document.write( "    - Using systems of equations to solve problems on investment\r
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\n" ); document.write( "\n" ); document.write( "Solution\r
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document.write( "Let x = the amount invested at 7% annual simple interest.\r\n" );
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document.write( "Then the amount invested at 4% is (32000-x) dollars.\r\n" );
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document.write( "Your basic equation is\r\n" );
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document.write( "    interest + interest       = total interest,    or\r\n" );
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document.write( "    0.07x    + 0.04*(32000-x) = 1670\r\n" );
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document.write( "Simplify and solve for x:\r\n" );
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document.write( "    x = \"%281670+-0.04%2A32000%29%2F%280.07+-+0.04%29\" = 13000.\r\n" );
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document.write( "ANSWER.  $13000 were invested at 7% and the rest,  $32000- $13000 = $19000 were invested at 4%.\r\n" );
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document.write( "CHECK.    0.07*13000 + 0.04*19000 = 1670 dollars.    ! Correct !\r\n" );
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\n" ); document.write( "\n" ); document.write( "It is a standard and typical problem on investments.\r
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\n" ); document.write( "\n" ); document.write( "As I just said,  if you need more details,  or if you want to see other similar problems solved by different methods,  look into the lesson \r
\n" ); document.write( "\n" ); document.write( "    - Using systems of equations to solve problems on investment\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "You will find there different approaches  (using one equation or a system of two equations in two unknowns),  as well as
\n" ); document.write( "different methods of solution to the equations  (Substitution,  Elimination).\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lesson is the part of this online textbook under the topic  \"Systems of two linear equations in two unknowns\".\r
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\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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