document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=446950>Question 446950</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need an exponential decay growth for this problem:\r<BR>\n" );
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document.write( "The first cleaning takes you 135 minutes.  You notice that for each cleaning after that, you decrease the time it takes from the week before by one-fifth.  I need to deterine the function to model.\r<BR>\n" );
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document.write( "I'm thinking it is y=(1/5)^x, but I'm not sure.\r<BR>\n" );
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document.write( "Thanks for your help. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #307771 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=307771\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If each successive time is reduced by 1/5, that means that the current week's<BR>\n" );
document.write( "time is 4/5 the time of the previous week.  <BR>\n" );
document.write( "Let x = the number of weeks after the 1st week, y = the cleaning time.<BR>\n" );
document.write( "Since the initial time is 135 min. we can express the time for a given week as:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+135%284%2F5%29%5Ex ALIGN=MIDDLE  ALT=\"y+=+135%284%2F5%29%5Ex\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "For the 1st week, x=0, so y = 135 min.<BR>\n" );
document.write( "For the 2nd week, x=1, so y = (4/5)135 = 108 min., etc. </SPAN>\n" );
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