document.write( "Question 1124848: A college student earned $7200 during summer vacation working as a waiter in a restaurant on the boardwalk at the beach. The student invested part of the money at 10% and the rest at 9%. If the student received a total of $680 in interest at the end of the year, how much was invested at 10% \r
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Algebra.Com's Answer #741148 by ikleyn(52788)\"\" \"About 
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document.write( "Let x = the amount invested at 10%.\r\n" );
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document.write( "Then the amount invested at 9% is the rest (7200-x) dollars.\r\n" );
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document.write( "The annual interest from the 10% account is 0.1x, while from the 9% account it is 0.09*(7200-x).\r\n" );
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document.write( "Your equation is\r\n" );
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document.write( "interest + interest      = total interest,     or\r\n" );
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document.write( "0.1x     + 0.09*(7200-x) = 680.\r\n" );
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document.write( "Simplify and solve for x.\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( "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
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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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