document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=996757>Question 996757</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Polluted water is passed through a series of filters.  Each filter removes 59% of the remaining impurities. Initially the water contains impurities at a level of 400 parts per million (ppm).  Determine a rule for the function g , that gives the remaining level of impurities, L , after the water has passed through a series of n  filters.<BR>\n" );
document.write( "G(n)=?????\r<BR>\n" );
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document.write( "Thanks! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #615065 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=615065\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> each filter removes 59% of the remaining impurities.\r<BR>\n" );
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document.write( "remaining level of impurity equals 41% of the original impurity.\r<BR>\n" );
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document.write( "example:\r<BR>\n" );
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document.write( "400 parts per million start with.<BR>\n" );
document.write( "pass through filter once.<BR>\n" );
document.write( "remove .59 * 400 = 235<BR>\n" );
document.write( "remaining = .41 * 400 = 164<BR>\n" );
document.write( "235 + 164 = 400.\r<BR>\n" );
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document.write( "you can use .41 as the factor for the remaining impurities.\r<BR>\n" );
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document.write( "400 * .41 = 164 * .41 = 67.24 * .41 = 27.5684\r<BR>\n" );
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document.write( "basically you have 400 * .41 * .41 * .41 which is the same as 400 * .41^3\r<BR>\n" );
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document.write( "400 * .41^3 = 27.5684.\r<BR>\n" );
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document.write( "this works for any number of times you pass though the filter.\r<BR>\n" );
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document.write( "g(n) = 400 * .41^n\r<BR>\n" );
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document.write( "when n = 3, g(3) = 400 * .41^3 = 27.5684.\r<BR>\n" );
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document.write( "you could have used any variable name, such as x, as well.\r<BR>\n" );
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document.write( "g(x) = 400 * .41^x\r<BR>\n" );
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document.write( "when x = 3, g(3) = 400 * .41^3 = 27.5684.\r<BR>\n" );
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