document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=198168>Question 198168</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A bacteria population starts at 2032 and decrease by 15% everyday. \r<BR>\n" );
document.write( "\n" );
document.write( "Write a function representing the number of bacteria present each day. \r<BR>\n" );
document.write( "\n" );
document.write( "After how many days will there be fewer than 321 bacteria?\r<BR>\n" );
document.write( "\n" );
document.write( "I need some help on this problem please. \r<BR>\n" );
document.write( "\n" );
document.write( "Thank you in advance.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #148635 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=148635\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A bacteria population starts at 2032 and decrease by 15% everyday.<BR>\n" );
document.write( "Write a function representing the number of bacteria present each day.<BR>\n" );
document.write( "f(t) = 2032(1-.15)^t<BR>\n" );
document.write( "f(t) = 2032*.85^t<BR>\n" );
document.write( ":<BR>\n" );
document.write( "After how many days will there be fewer than 321 bacteria?<BR>\n" );
document.write( "2032*.85^t = 321<BR>\n" );
document.write( ".85^t = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=321%2F2032 ALIGN=MIDDLE  ALT=\"321%2F2032\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".85t = .1578<BR>\n" );
document.write( "t*log(.85) = log(.1578)<BR>\n" );
document.write( "-.07058t = -.80189<BR>\n" );
document.write( "t  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28-.80189%29%2F%28-.07058%29 ALIGN=MIDDLE  ALT=\"%28-.80189%29%2F%28-.07058%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "t = 11.36 days<BR>\n" );
document.write( "We can say after 12 days there will be less than 321<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Check solution on calc: enter 2032*.85^12 = 289 left which is less than 321<BR>\n" );
document.write( "in 11 days: 2032*.85^11 = 340, more than 321  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );