document.write( "Question 612870: From a class of girls and boys, the probability that one student chosen at random will be a boy is 2/3. If 3 girls leave the class, the probability that a student chosen at random will be a boy is 4/5. How many boys and girls are ther in the class before the 3 girls leave?\r
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Algebra.Com's Answer #385765 by stanbon(75887)\"\" \"About 
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From a class of girls and boys, the probability that one student chosen at random will be a boy is 2/3. If 3 girls leave the class, the probability that a student chosen at random will be a boy is 4/5. How many boys and girls are ther in the class before the 3 girls leave?
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\n" ); document.write( "P(b) = 2/3
\n" ); document.write( "b/(b+g) = 2/3
\n" ); document.write( "3b = 2b+2g
\n" ); document.write( "b = (2/3)b + (2/3)g
\n" ); document.write( "(1/3)b = (2/3)g
\n" ); document.write( "b = 2g\r
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\n" ); document.write( "Equation:\r
\n" ); document.write( "\n" ); document.write( "b/(b + g-3) = 4/5
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\n" ); document.write( "(2g)/(2g + g-3) = 4/5
\n" ); document.write( "10g = 4(3g-3)
\n" ); document.write( "10g = 12g-12
\n" ); document.write( "2g = 12
\n" ); document.write( "g = 6 (original # of girls)
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\n" ); document.write( "b = 2g = 12 (original # of boys)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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