document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1050947>Question 1050947</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A certain virus infects one in every 400 people. A test used to detect the virus in a person is positive 90% of the time if the person has the virus and 10% of the time if the person does not have the virus. Let A be the event \"the person is infected\" and B be the event \"the person tests negative.\"\r<BR>\n" );
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document.write( "(a) Find the probability that a person has the virus given that they have tested positive.\r<BR>\n" );
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document.write( "(b) Find the probability that a person does not have the virus given that they have tested negative. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #666550 by </B><A HREF=/tutors/aboutme.mpl?userid=EliteCracker><B>EliteCracker(4)</B></A><img src=\"/images/stars/iconNewId_16x16.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=EliteCracker><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=666550\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 90% of 100% = 9/10\r<BR>\n" );
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document.write( "Answer to part A is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9%2F10 ALIGN=MIDDLE  ALT=\"9%2F10\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "10% of 100% = 1/10\r<BR>\n" );
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document.write( "Answer to part B is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F10 ALIGN=MIDDLE  ALT=\"1%2F10\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "CHECK<BR>\n" );
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document.write( "90% of 400 = 360 infected people<BR>\n" );
document.write( "360/400 = 9/10<BR>\n" );
document.write( "Every 9 of 10 people are infected.\r<BR>\n" );
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document.write( "10% of 400 = 40 infected people<BR>\n" );
document.write( "40/400 = 1/10<BR>\n" );
document.write( "Every 1 of 10 people are not infected. </SPAN>\n" );
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