document.write( "Question 970249: 0.35 of the pupils in a class are girls.If they are 18 more boys than girls,how many boys are in the class? \n" ); document.write( "

Algebra.Com's Answer #592895 by LinnW(1048) $\"\"$ $\"About$

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Let B be the number of boys, and G be the number of girls.
\n" ); document.write( "Since there are 18 more boys than girls,
\n" ); document.write( "B = G + 18
\n" ); document.write( "Since 0.35 are girls,
\n" ); document.write( " $\"35%2F100+=+%28G%2F%28all+pupils%29%29\"$
\n" ); document.write( " $\"35%2F100+=+%28G%2F%28B%2BG%29%29\"$
\n" ); document.write( "do cross products
\n" ); document.write( "100G = 35(B+G)
\n" ); document.write( "Now substitute ( G + 18 ) for B
\n" ); document.write( "100G = 35(G+18) + 35G
\n" ); document.write( "100G = 35G + 630 + 35G
\n" ); document.write( "100G = 70G + 630
\n" ); document.write( "add -70G to each side
\n" ); document.write( "30G = 630
\n" ); document.write( "Divide each side by 30
\n" ); document.write( "G = 21
\n" ); document.write( "Since B = G + 18
\n" ); document.write( "B = 21 + 18 = 39
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