document.write( "Question 1069073: Sandy is 7 years younger than Mandy, in 4 years time sandy will be half Mandy's age. What are their ages presently \n" ); document.write( "

Algebra.Com's Answer #684320 by ikleyn(52800) $\"\"$ $\"About$

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\n" ); document.write( "Sandy is 7 years younger than Mandy, in 4 years time sandy will be half Mandy's age. What are their ages presently
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document.write( "Let S be the Sandy's present age, M be that of Mandy.\r\n" );
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document.write( "S = M -7,                (1)\r\n" );
document.write( "S + 4 = .        (2)\r\n" );
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document.write( "Multiply eq(2) by 2 (both sides). You will get the system in this form\r\n" );
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document.write( "S = M -7,                (1')\r\n" );
document.write( "2S + 8 = M+4.            (2')\r\n" );
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document.write( "Substitute the expression (1') for S into (2'), replacing S. You will get\r\n" );
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document.write( "2*(M-7) + 8 = M+4   --->\r\n" );
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document.write( "2M - 14 + 8 = M + 4 --->  M = 14 - 8 + 4 = 10.\r\n" );
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document.write( "Answer.  Mandy's present age is 10 years.  Sandy's present age is 10-7 = 3 yeras.\r\n" );
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\n" ); document.write( "\n" ); document.write( "There is a bunch of lessons on age word problems \r
\n" ); document.write( "\n" ); document.write( "    - Age problems and their solutions\r
\n" ); document.write( "\n" ); document.write( "    - A fresh formulation of a traditional age problem\r
\n" ); document.write( "\n" ); document.write( "    - Really intricate age word problem\r
\n" ); document.write( "\n" ); document.write( "    - Selected age word problems from the archive\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Read them and become an expert in solving age problems.\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 lessons are the part of this online textbook under the topic \"Age word problems\".\r
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