document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1019618>Question 1019618</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Starting with a sum of 4,638.40 I must find a way to subtract 25% from the sum a total of 162 times until I deplete the sum and enter negative numbers.  I'm putting this into an Excel spreadsheet. It's been decades since I've been in math class. Which algebraic formula would I use?  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 #635569 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=635569\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A1=4638.40<BR>\n" );
document.write( "A2=(0.75*A1), which is 25% less than 4638.40<BR>\n" );
document.write( "A3=(0.75*A2), etc.<BR>\n" );
document.write( "There are more elegant ways to do this, but it will work, EXCEPT it never become negative.  It will become 0 to some number of decimal places, and you can't subtract 25% of 0 and get a negative difference. Perhaps if this were 2,5%, it would be close to zero ($76.75) after 162 iterations. <BR>\n" );
document.write( "------------------------\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );