document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=701494>Question 701494</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If the population is decreasing at 2.3% per year and the population is currently 125,000. What is the exponentional model? What will the population be in 15 years? How long will it take to reach 25,000.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #432447 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=432447\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  If the population is decreasing at 2.3% per year and the population is currently 125,000. What is the exponentional model? What will the population be in 15 years? How long will it take to reach 25,000. <BR>\n" );
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document.write( "Each year 97.7% of last year's population survives.<BR>\n" );
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document.write( "A(t) = 125000(0.977)^t<BR>\n" );
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document.write( "Solve 125000(0.977)^t = 25000<BR>\n" );
document.write( "0.977^t = 1/5<BR>\n" );
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document.write( "Take the log and solve for \"t\":<BR>\n" );
document.write( "t = log(1/5)/log(0.977)<BR>\n" );
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document.write( "t = 69 years<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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