document.write( "Question 938790: there are twice as many boys in a room as girls. if 5 boys leave the room, there would be a equal number of boys and girls in the room. how many boys were in the room at first. \n" ); document.write( "
Algebra.Com's Answer #571971 by Edwin McCravy(20055)\"\" \"About 
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document.write( "Without using algebra:\r\n" );
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document.write( "Since there were twice as many boys as girls, think of dividing the\r\n" );
document.write( "boys into two equal groups, and letting all the girls be a third group.\r\n" );
document.write( "Then each of those 3 groups would have the same number of people. \r\n" );
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document.write( "Then if 1 of those groups of boys left the room, there would be just two\r\n" );
document.write( "equal groups, one of boys and 1 or girls.  \r\n" );
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document.write( "So the 5 boys that left must have been one of those groups.  So at first,\r\n" );
document.write( "there were 10 boys and 5 girls in the room.\r\n" );
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document.write( "Using algebra:\r\n" );
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document.write( "\"system%28b+=+2g%2Cb-5=g%29\"\r\n" );
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document.write( "Substitute (2g) for b in the second equation:\r\n" );
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document.write( "\"b-5=g\"\r\n" );
document.write( "\"2g-5=g\"\r\n" );
document.write( "\"g=5\"\r\n" );
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document.write( "Substitute (5) for g in \"b=2g\"\r\n" );
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document.write( "\"b=2%285%29=10\"\r\n" );
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document.write( "10 boys and 5 girls in the room at first.\r\n" );
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document.write( "Edwin
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