document.write( "Question 1067713: Of the 100 students enrolled at the dance studio, 50 take ballet
\n" ); document.write( "and 24 take tap dancing. Eight of the students who take ballet
\n" ); document.write( "also take tap dancing. If a student at the studio is chosen at
\n" ); document.write( "random, find the probability that they take ballet, if it is
\n" ); document.write( "known that they do not take tap dancing. I already got that
\n" ); document.write( "50-8=42. Now I am stumped. \n" ); document.write( "
Algebra.Com's Answer #682869 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "You should begin by making a complete Venn diagram with 2 sets.\r\n" );
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document.write( "Start with the 8 in the middle region which take both ballet and\r\n" );
document.write( "tap.  Then do as you did and subtract 8 from the 50, getting\r\n" );
document.write( "42 who take ballet only.  Then subtract the same 8 from 24, getting\r\n" );
document.write( "16 who take tap only.  Then find the number who take ballet or tap\r\n" );
document.write( "or both 42+8+16 = 66.  Then since there are 100 students in all,\r\n" );
document.write( "that means that 100-66 = 34 do not take either ballet or tap. (I\r\n" );
document.write( "suppose they take ballroom dancing or jazz). Put those 34 outside\r\n" );
document.write( "both circles.  I put it in the bottom left corner of the rectangle.\r\n" );
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document.write( "Now to get the desired conditional probability, find the reduced\r\n" );
document.write( "sample space by erasing all the tap dancers. \r\n" );
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document.write( "Now the reduced sample space contains only 42+34 or 76.  \r\n" );
document.write( "So the conditional probability is 42 out of 76 or 42/76 \r\n" );
document.write( "which reduces to 21/38. \r\n" );
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document.write( "Edwin
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