document.write( "Question 574661: Mary is 24.
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\n" ); document.write( "is now.
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Algebra.Com's Answer #369209 by Edwin McCravy(20056) $\"\"$ $\"About$

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Mary is 24.
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\n" ); document.write( "is now.
\n" ); document.write( "How old is Ann?
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document.write( "Let A = Ann's age now\r\n" );
document.write( "Let y = the number of years ago it was when Mary was Ann's present age, or A.\r\n" );
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document.write( "Then y years ago, Mary was 24-y and she was also A, so we set those equal:\r\n" );
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document.write( "       24-y = A \r\n" );
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document.write( "Also y years ago, Ann was A-y, and Mary's age now, 24, is twice this, so\r\n" );
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document.write( "         24 = 2(A-y) \r\n" );
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document.write( "So that is the system of equations:\r\n" );
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document.write( "Solve that system by substitution and get A = 18 and y=6\r\n" );
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document.write( "Answer: Ann is 18.\r\n" );
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document.write( "Checking:  Ann is now 18. Mary is now 24, so 6 years ago Mary was 18, which\r\n" );
document.write( "is Ann's age now.  That checks.  6 years ago Ann was 12.  Since Mary's age now\r\n" );
document.write( "is 24, she is indeed twice as old as Ann was 6 years ago.  So the answer is correct.\r\n" );
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document.write( "Edwin

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