document.write( "Question 474181: Two sisters, Mary and Jane have a total age of 98. When Mary was Jane's age, Jane was half as old as Mary is now. What are their ages?\" \n" ); document.write( "

Algebra.Com's Answer #325216 by Edwin McCravy(20055) $\"\"$ $\"About$

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Two sisters, Mary and Jane have a total age of 98. When Mary was Jane's age, Jane was half as old as Mary is now. What are their ages?\"
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document.write( "Let M = Mary's age now\r\n" );
document.write( "Let J = Jane's age now\r\n" );
document.write( "Let x be the number of years ago it was when Mary was Jane's age\r\n" );
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\n" ); document.write( "Mary and Jane have a total age of 98.
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document.write( "That says \r\n" );
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document.write( "M + J = 98\r\n" );
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\n" ); document.write( "When Mary was Jane's age
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document.write( "That says \"x years ago Mary was Jane's age now\"\r\n" );
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document.write( "M - x = J\r\n" );
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\n" ); document.write( "Jane was half as old as Mary is now
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document.write( "That says \"x years ago Jane was M\r\n" );
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document.write( "J - x = M\r\n" );
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document.write( "So we have this system of three equations in three unknowns:\r\n" );
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document.write( "If you don't know how to solve that system, post again asking how.\r\n" );
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document.write( "Answer: J = 42, M = 56, x = 14.\r\n" );
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document.write( "Checking:  \r\n" );
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\n" ); document.write( "Mary and Jane have a total age of 98.
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document.write( "That checks because 56 + 42 = 98\r\n" );
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\n" ); document.write( "When Mary was Jane's age,
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document.write( "x = 14 years ago Mary was 56 - 14 or 42, Jane's age now.  That checks.\r\n" );
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\n" ); document.write( "Jane was half as old as Mary is now.
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document.write( "x = 14 years ago, Jane was 42 - 14 or 28, and indeed 28 is half as old as\r\n" );
document.write( "56, Mary's present age.\r\n" );
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document.write( "So that is correct.\r\n" );
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document.write( "Edwin

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