document.write( "Question 123538: Sam is 2 years older than her brother. 12 years ago, she was twice as old as he was. How old are they now? \n" ); document.write( "

Algebra.Com's Answer #90645 by Edwin McCravy(20056) $\"\"$ $\"About$

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Sam is 2 years older than her brother. 12 years ago, she was twice as old as he was. How old are they now?
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document.write( "The best way to learn to set up word problems is to practice \r\n" );
document.write( "looking up the answer first, then checking it to see why it is \r\n" );
document.write( "the correct answer.  That's because it takes te same thinking\r\n" );
document.write( "to check a problem as it does to set it up.\r\n" );
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document.write( "So I'll start by telling you the answer. Then we'll set it up\r\n" );
document.write( "to show how it was obtained, and you'll see it was the same\r\n" );
document.write( "thinking as checking the problem:\r\n" );
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document.write( "The answer:  Her brother is 14, so Sam is 16. \r\n" );
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document.write( "Checking:\r\n" );
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document.write( "Sam is 2 years older than her brother, who is 14, so she is 14+2, (or 16). \r\n" );
document.write( "12 years ago, she was 16-12, (or 4) and he was 14-12, (or 2), and 4 equals\r\n" );
document.write( "twice 2, so she was twice as old as he was. \r\n" );
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document.write( "Let B = her brother's age\r\n" );
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document.write( "Setting it up:\r\n" );
document.write( "Sam is 2 years older than her brother, who is B, so she is B+2.\r\n" );
document.write( "12 years ago, she was (B+2)-12 and he was B-12, and (B+2)-12 equals \r\n" );
document.write( "twice B-12, so she was twice as old as he was. \r\n" );
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document.write( "To set up the equation you only need these words:\r\n" );
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document.write( "(B+2)-12 equals twice B-12\r\n" );
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document.write( "or\r\n" );
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document.write( "(B + 2) - 12 = 2(B - 12)\r\n" );
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document.write( "Solve that and get B = 14, then Sam is 2 years older, or 16.\r\n" );
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document.write( "Edwin

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