document.write( "Question 1141272: A survey of 100 photographers found: 60 take black and white photographs, 75 take color photographs and 45 take both types of photographs.\r
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\n" ); document.write( "use a venn diagram as part of your answer
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Algebra.Com's Answer #761791 by Edwin McCravy(20054)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "60 take black and white photographs,
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document.write( "The red circle contains the 60 photographers that take black and white\r\n" );
document.write( "photographs.  They are split between the regions a and b, and we don't yet\r\n" );
document.write( "know how many of the 60 go in region a and how many go in region b.\r\n" );
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75 take color photographs
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document.write( "The blue circle contains the 75 photographers that take color photographers.\r\n" );
document.write( "They are split between the regions b and c, and we don't yet know how many\r\n" );
document.write( "of the 75 go in region b and how many go in region c.\r\n" );
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document.write( "The three regions a,b and c contain:\r\n" );
document.write( "1. The photographers in region a take ONLY black and white photographs. \r\n" );
document.write( "2. The photographers in region b take BOTH black and white photographs and\r\n" );
document.write( "   color photographs.\r\n" );
document.write( "3. The photographers in region c take ONLY color photographs.\r\n" );
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and 45 take both types of photographs
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document.write( "Now we have something definite. We know that region b contains 45\r\n" );
document.write( "photographers.  So we write 45 in region b, the middle region, the\r\n" );
document.write( "overlapping part of the two circles:\r\n" );
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document.write( "Now since we know that the red circle contains 60 photographers and that\r\n" );
document.write( "the overlapping part contains 45, we know that region a contains the other\r\n" );
document.write( "60-45 or 15 photographers.  So we put 15 in the leftmost region, region a:\r\n" );
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document.write( "Now we see that the red circle contains a total of 60 photographers. Since\r\n" );
document.write( "we know that the blue circle contains 75 photographers and that the\r\n" );
document.write( "overlapping part b contains 45, we know that region a contains the other \r\n" );
document.write( "75-45 or 30 photographers.  So we put 30 in the rightmost region, region c:\r\n" );
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document.write( "Now you see that the blue circle contains a total of 75 photographers.  The\r\n" );
document.write( "question is:\r\n" );
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How many take color, but not black and white photographs?
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document.write( "Answer: 30\r\n" );
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document.write( "Edwin

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