document.write( "Question 395636: A boy said I have as many brothers as i have sisters.Then his sister said i have double the number of brothers as i have sistes.Find the number of brothers and sisters. \n" ); document.write( "

Algebra.Com's Answer #280769 by Edwin McCravy(20060) $\"\"$ $\"About$

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A boy said I have as many brothers as i have sisters.Then his sister said i have double the number of brothers as i have sistes.Find the number of brothers and sisters.
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document.write( "Let b = the number of boys in the family\r\n" );
document.write( "Let g = the number of girls in the family\r\n" );
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document.write( "The boy has b-1 brothers.  We must subtract 1 from b,\r\n" );
document.write( "the number of boys, since the boy who spoke is not his own brother.\r\n" );
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document.write( "The boy has g sisters.  So\r\n" );
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document.write( "b-1 = g\r\n" );
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document.write( "The girl has g-1 sisters.  We must subtract 1 from g, the number of \r\n" );
document.write( "girls, since the girl who spoke is not her own sister.\r\n" );
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document.write( "The girl has b brothers.  So\r\n" );
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document.write( "b = 2(g-1)\r\n" );
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document.write( "So we have this system of equations:\r\n" );
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document.write( "b-1 = g\r\n" );
document.write( "  b = 2(g-1)\r\n" );
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document.write( "Use substitution:\r\n" );
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document.write( "2(g-1)-1 = g\r\n" );
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document.write( "  2g-2-1 = g\r\n" );
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document.write( "    2g-3 = g\r\n" );
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document.write( "       g = 3\r\n" );
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document.write( "b = 2(3-1)\r\n" );
document.write( "b = 2(2)\r\n" );
document.write( "b = 4\r\n" );
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document.write( "There are 3 girls and 4 boys.\r\n" );
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document.write( "Each boy has 3 brothers and 3 sisters\r\n" );
document.write( "Each girl has 4 brothers and 2 sisters.  \r\n" );
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document.write( "Edwin

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