document.write( "Question 995527: Out of 100 persons 50 drink Pepsi, 40 drink Coke and 20 drink both Pepsi and
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Algebra.Com's Answer #614261 by Edwin McCravy(20060)\"\" \"About 
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document.write( "Out of 100 persons 50 drink Pepsi, 40 drink Coke and 20 drink both Pepsi and\r\n" );
document.write( "Coke. The number of persons who neither drink Pepsi nor Coke is ___.\r\n" );
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document.write( "Set P, which is composed of regions \"a\" and \"b\", contains as \r\n" );
document.write( "elements all 50 people who drink Pepsi.\r\n" );
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document.write( "Set C, which is composed of regions \"b\" and \"c\", contains as \r\n" );
document.write( "elements all 40 people who drink Coke.  \r\n" );
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document.write( "We first look at this sentence:\r\n" );
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document.write( ">> 20 drink both pepsi and coke <<\r\n" );
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document.write( "That means there are 20 people in the overlapping part of the two \r\n" );
document.write( "circles, which is the region labeled \"b\".\r\n" );
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document.write( "So we put 20 instead of \"b\":\r\n" );
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document.write( "We see the words:\r\n" );
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document.write( ">>50 drink pepsi<<\r\n" );
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document.write( "We have already accounted for 20 of the 50, so the remaining 50-20 or 30\r\n" );
document.write( "are in the region of set A labeled \"a\", so we put 30 where the \"a\" is:\r\n" );
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document.write( "Then we see the words:\r\n" );
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document.write( ">>40 drink Coke<<\r\n" );
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document.write( "We have already accounted for 20 of the 40, so the remaining 40-20 or 20\r\n" );
document.write( "are in the region of set B labeled \"c\", so we put 20 where the \"c\" is:\r\n" );
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document.write( "Finally we see the words:\r\n" );
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document.write( ">>100 persons<<\r\n" );
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document.write( "We have already accounted for the number of elements of the three \r\n" );
document.write( "regions in the circles. So we add what we have 30+20+20=70 so the \r\n" );
document.write( "remaining 100-70=30 must be in the region outside both circles \r\n" );
document.write( "but inside the rectangle, which is the universal set, so we put \r\n" );
document.write( "30 in the outer region labeled \"d\": \r\n" );
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document.write( "So the answer is 30.\r\n" );
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document.write( "Edwin
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