document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=298753>Question 298753</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose that the world population is increasing at an annual rate of 2%. If we assume an exponential growth model, in how many years will the population double? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #214906 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=214906\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">     Suppose that the world population is increasing at an annual rate of 2%. If we assume an exponential growth model, in how many years will the population double?<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Exponential growth can be modeled as:<BR>\n" );
document.write( "A(t) = Pe^(rt)<BR>\n" );
document.write( "where<BR>\n" );
document.write( "A(t) is the population at time t<BR>\n" );
document.write( "P is the initial population <BR>\n" );
document.write( "r is the growth rate<BR>\n" );
document.write( "t is time<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Let P = initial population<BR>\n" );
document.write( "then<BR>\n" );
document.write( "2P = Pe^(.02t)<BR>\n" );
document.write( "2 = e^(.02t)<BR>\n" );
document.write( "ln 2 = .02t<BR>\n" );
document.write( "ln 2/(.02) = t<BR>\n" );
document.write( "34.66 years = t </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );