document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=779483>Question 779483</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose that in any given year, the number of cases of a disease is reduced by 20%. If there are 10000 cases today, how many years will it take to reduce the number of cases to 1000? Be sure to write the exponential equation used.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #475233 by </B><A HREF=/tutors/aboutme.mpl?userid=reviewermath><B>reviewermath(1029)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=reviewermath><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=reviewermath><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=475233\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Q:<BR>\n" );
document.write( "Suppose that in any given year, the number of cases of a disease is reduced by 20%. If there are 10000 cases today, how many years will it take to reduce the number of cases to 1000? Be sure to write the exponential equation used. <BR>\n" );
document.write( "---------------------------------------------------------------------------<BR>\n" );
document.write( "A:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A%28t%29+=+a%5B0%5D%281+-+r%29%5Et ALIGN=MIDDLE  ALT=\"A%28t%29+=+a%5B0%5D%281+-+r%29%5Et\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1000+=+10000%281+-+0.2%29%5Et ALIGN=MIDDLE  ALT=\"1000+=+10000%281+-+0.2%29%5Et\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.8%5Et+=+0.1 ALIGN=MIDDLE  ALT=\"0.8%5Et+=+0.1\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+log%280.8%2C+0.1%29 ALIGN=MIDDLE  ALT=\"t+=+log%280.8%2C+0.1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > &#8776; 10.31885 years<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );