document.write( "Question 1123789: Susan invests 3 times as much money at 11% as she does at 7%. If her total interest after 1 year is $1600, how much does she have invested at each rate?
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Algebra.Com's Answer #740187 by ikleyn(52776) $\"\"$ $\"About$

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document.write( "Let x be the amount Susan invested at 7%.\r\n" );
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document.write( "Then the amount invested at 11% is 3x dollars.\r\n" );
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document.write( "Your equation is\r\n" );
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document.write( "    0.07x + 0.11*(3x) = 1600.\r\n" );
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document.write( "    0.07x + 0.33x = 1600\r\n" );
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document.write( "    0.4x = 1600  ====>  x =  = 4000 dolars.\r\n" );
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document.write( "Answer.  $4000  at  7%  and  $12000  at 11%.\r\n" );
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document.write( "Check.   0.07*4000 + 0.11*12000 = 1600 dollars.    ! Correct !\r\n" );
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