document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1131618>Question 1131618</A>: <I><SPAN STYLE=\"word-break: break-all;\"> During one month, a blood donation center found that<BR>\n" );
document.write( "45.3% of the donors had the A antigen.<BR>\n" );
document.write( "14.7% of the donors had the B antigen.<BR>\n" );
document.write( "4.7% of the donors had the A antigen and the B antigen.<BR>\n" );
document.write( "84.3% of the donors were Rh+.<BR>\n" );
document.write( "87.5% of the donors had the B antigen or were Rh+.<BR>\n" );
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document.write( "Find the percent of donors that have the A antigen or the B antigen.<BR>\n" );
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document.write( "Find the percent of donors that have the B antigen and are Rh+. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #748869 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52784)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=748869\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .\r<BR>\n" );
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document.write( "(a) &nbsp;&nbsp;<U>Find the percent of donors that have the A antigen or the B antigen.</U>\r<BR>\n" );
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document.write( "     The basic equality is  P(A or B) = P(A) + P(B) - P(A and B),  which gives\r\n" );
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document.write( "                            P(A or B) = 45.3% + 14.7% - 4.7% = 55.3%.    <U>ANSWER</U>\r\n" );
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document.write( "(b) &nbsp;&nbsp;<U>Find the percent of donors that have the B antigen and are Rh+.</U>\r<BR>\n" );
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document.write( "     The basic equality is  P(B or Rh+) = P(B) + P(Rh+) - P(B and Rh+),   which  implies\r\n" );
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document.write( "                            P(B and Rh+) = P(B) + P(Rh+) - P(B or Rh+),   or\r\n" );
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document.write( "                            P(B and Rh+) = 14.7% + 84.3% - 87.5% = 11.5%.     <U>ANSWER</U>\r\n" );
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document.write( "<U>The lesson to learn from my post is THIS</U>\r<BR>\n" );
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document.write( "    basic equality  for probability  is   P(A or B) = P(A) + P(B) - P(A and B).\r\n" );
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document.write( "    It is true for any sets of events  \" A \"  and  \" B \"  inside the universal set of events.\r\n" );
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document.write( " </SPAN>\n" );
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