document.write( "Question 76181This question is from textbook
\n" ); document.write( ": From a class of girls and boys, the probability that one student chosen at random will be a girl is 1/3. If four boys leave the class, the probability that a student chosen at random will be a girl is 2/5. How many boys and girls are there in the class before the four boys leave? \n" ); document.write( "
Algebra.Com's Answer #54669 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 girl is 1/3. If four boys leave the class, the probability that a student chosen at random will be a girl is 2/5. How many boys and girls are there in the class before the four boys leave?
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\n" ); document.write( "Let \"b\" be # of boys; Let \"g\" be # of girls.
\n" ); document.write( "EQUATIONS:
\n" ); document.write( "g/b=1/3
\n" ); document.write( "g/(b-4)=2/5
\n" ); document.write( "----------
\n" ); document.write( "b-3g=0
\n" ); document.write( "2b-8=5g
\n" ); document.write( "or
\n" ); document.write( "2b-5g=8
\n" ); document.write( "And mulriplying the 1st equation by 2 you get:
\n" ); document.write( "2b-6g=0
\n" ); document.write( "-------------
\n" ); document.write( "Subtract one from the other to get:
\n" ); document.write( "g=8 (number of girls)
\n" ); document.write( "Substitute to get
\n" ); document.write( "b=3g=24 (number of boys)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "Stan H. \n" ); document.write( "
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