document.write( "Question 661745: translate to variable expression and solve.\r
\n" ); document.write( "\n" ); document.write( "if mary is 24 years old. mary is twice as old as Ann was, when Mary was as old as Ann is now. How old is Ann. \n" ); document.write( "
Algebra.Com's Answer #411782 by Edwin McCravy(20054)\"\" \"About 
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document.write( "Mary is 24 years old.  \r\n" );
document.write( "Let Ann be A years old. \r\n" );
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document.write( "Mary is twice as old as Ann was x years ago, which was (A - x). \r\n" );
document.write( "Also x years ago, Mary was (24 - x), and that is how old Ann is now,\r\n" );
document.write( "which is A. \r\n" );
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document.write( "x years ago, Mary was 24 - x\r\n" );
document.write( "x years ago, Ann was A - x\r\n" );
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document.write( "So the equations comes from:\r\n" );
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document.write( "         \"%28matrix%283%2C1%2C%0D%0A%0D%0A%22Mary%27s%22%2C+age%2C+now%29%29\" = 2·\"%28matrix%285%2C1%2C%0D%0A%0D%0A%22Ann%27s%22%2C+age%2C+x%2C+years%2C+ago%29%29\"\r\n" );
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document.write( "and\r\n" );
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document.write( "         \"%28matrix%285%2C1%2C%0D%0A%0D%0A%22Mary%27s%22%2C+age%2C+x%2Cyears%2C+ago%29%29\" = \"%28matrix%283%2C1%2C%0D%0A%0D%0A%22Ann%27s%22%2C+age%2C+now%29%29\"\r\n" );
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document.write( "So the system of equations is\r\n" );
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document.write( "                24 = 2(A - x)\r\n" );
document.write( "                24 - x = A\r\n" );
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document.write( "Solve that system and get x = 6 and A = 18.\r\n" );
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document.write( "So 6 years ago Ann was 12 and Mary is twice that now.\r\n" );
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document.write( "Edwin
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