document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1130047>Question 1130047</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The spread of a flu virus in a community of 45,000 people is given by the function <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=f%28t%29+=+%2845000%29%2F%281%2B224e%5E%28-899t%29%29 ALIGN=MIDDLE  ALT=\"f%28t%29+=+%2845000%29%2F%281%2B224e%5E%28-899t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > where f(t) is the number of people in infected in week t.\r<BR>\n" );
document.write( "\n" );
document.write( "When will half of the town be infected? (Show all work and give exact answers). </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #746687 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13208)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=746687\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "I posted an answer to this problem previously, problem #1129948, answer #746566.<br><BR>\n" );
document.write( "In that answer, I assumed the exponential in the function was supposed to be e^(-0.899t) instead of e^(-899t).  Since the same problem is posted again, I will use the function as given.<br><BR>\n" );
document.write( "We want to find the number of weeks t when half of the town (22500 people) will be infected:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=22500+=+%2845000%29%2F%281%2B224e%5E%28-899t%29%29 ALIGN=MIDDLE  ALT=\"22500+=+%2845000%29%2F%281%2B224e%5E%28-899t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2B224e%5E%28-899t%29+=+2 ALIGN=MIDDLE  ALT=\"1%2B224e%5E%28-899t%29+=+2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=224e%5E%28-899t%29+=+1 ALIGN=MIDDLE  ALT=\"224e%5E%28-899t%29+=+1\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=e%5E%28-899t%29+=+1%2F224 ALIGN=MIDDLE  ALT=\"e%5E%28-899t%29+=+1%2F224\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-899t+=+ln%281%2F224%29 ALIGN=MIDDLE  ALT=\"-899t+=+ln%281%2F224%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+ln%281%2F224%29%2F-899 ALIGN=MIDDLE  ALT=\"t+=+ln%281%2F224%29%2F-899\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "which is equal to 0.00601963 weeks, to several decimal places.  That is equivalent to just over 1 hour -- which is not realistic. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );