document.write( "Question 1162273: Juanita invested $13,000 for one year, part at 9 percent annual interest and the rest at 7 percent annual interest. How much must she invest at 9 percent to get $1,000 in interest in a year?\r
\n" ); document.write( "\n" ); document.write( "Jonathon invested $8,400, part at 12 percent annual interest and the remainder at 8 percent annual interest. In one year, he earned three times as much interest from the 12 percent investment as he did from the 8 percent investment. How much interest did Jonathon earn at 8 percent interest?
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Algebra.Com's Answer #786041 by ikleyn(52778)\"\" \"About 
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document.write( "Let x be the amount invested at 9%.\r\n" );
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document.write( "Then the amount invested at 7% is the rest  (13000-x) dollars.\r\n" );
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document.write( "An equation for the total interest is\r\n" );
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document.write( "    0.09x + 0.07*(13000-x) = 1000   dollars.\r\n" );
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document.write( "From the equation\r\n" );
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document.write( "    x = \"%281000-0.07%2A13000%29%2F%280.09-0.07%29\" = 4500.\r\n" );
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document.write( "ANSWER.  $4500 invested at 9%  and the rest, 13000-4500 = 8500 dollars invested at 7%.\r\n" );
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\n" ); document.write( "\n" ); document.write( "It is a typical and standard problem on investment.\r
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\n" ); document.write( "\n" ); document.write( "To see many other similar solved problems on investment,  look into 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( "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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