document.write( "Question 766590: My brother says he has an equal number of brothers and sisters
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Algebra.Com's Answer #467106 by Edwin McCravy(20056)\"\" \"About 
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My brother says he has an equal number of brothers and sisters
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document.write( "Suppose there are B boys and G girls.\r\n" );
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document.write( "Your brother has B-1 brothers.  [He is not his own brother]\r\n" );
document.write( "Your brother has G sisters.\r\n" );
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document.write( "B-1 = G\r\n" );
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document.write( "Your sister has B brothers\r\n" );
document.write( "Your sister has G-1 sisters. [She is not her own sister]\r\n" );
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document.write( "B = 2(G-1)\r\n" );
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document.write( "So the system of equations is\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( "Substitute 2(G-1) for B in the first equation:\r\n" );
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document.write( "2(G-1)-1 = G\r\n" );
document.write( "  2G-2-1 = G\r\n" );
document.write( "    2G-3 = G\r\n" );
document.write( "       G = 3\r\n" );
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document.write( "Substitute 3 for G in\r\n" );
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document.write( "B-1 = G\r\n" );
document.write( "B-1 = 3\r\n" );
document.write( "  B = 4\r\n" );
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document.write( "There are 4 boys and 3 girls.\r\n" );
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document.write( "Edwin
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