document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=813672>Question 813672</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with this word problem.\r<BR>\n" );
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document.write( "The number of students infected with the flu on a college campus after t days is modeled by the function P(t)=240/(1+39e^0.3t .When will the number of infected students be 120?\r<BR>\n" );
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document.write( "a) about 16 days<BR>\n" );
document.write( "b) about 8 days<BR>\n" );
document.write( "c) about 12 days<BR>\n" );
document.write( "d) about 14 days\r<BR>\n" );
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document.write( "Thank you.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #489866 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=489866\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> P(t)=240/(1+39e^0.3t)<BR>\n" );
document.write( "It's hardly a \"word problem\" when you're given the equation.<BR>\n" );
document.write( "240/(1+39e^0.3t) = 120<BR>\n" );
document.write( "240/120 = (1+39e^0.3t)<BR>\n" );
document.write( "1+39e^0.3t = 2<BR>\n" );
document.write( "39e^0.3t = 1<BR>\n" );
document.write( "e^0.3t = 1/39<BR>\n" );
document.write( "ln(e^0.3t) = ln(1/39)<BR>\n" );
document.write( "0.3t = ln(1/39)<BR>\n" );
document.write( "t = ln(1/39)/0.3<BR>\n" );
document.write( "t =~ -12.212<BR>\n" );
document.write( "Doesn't seem right, does it? </SPAN>\n" );
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