document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1133595>Question 1133595</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The approximate population of a city in South Africa was 460 000 in 1970. In 1980, it was 630 000. Hint: A(t)= A0ekt. Determine the formula describing the population growth. Estimate the population in 2020. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #750852 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=750852\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A(t)=460e^kt, do to the number of thousands<BR>\n" );
document.write( "A(10)=630<BR>\n" );
document.write( "so 630=460*e^(10k)<BR>\n" );
document.write( "divide by 460 both sides<BR>\n" );
document.write( "e^10k-630/460<BR>\n" );
document.write( "ln both sides<BR>\n" );
document.write( "10k=ln(630/460)=0.3145<BR>\n" );
document.write( "k=0.03145\r<BR>\n" );
document.write( "\n" );
document.write( "2020 is t=50 and e^(kt)=e^50*0.03145=e^1.5725<BR>\n" );
document.write( "population is 460*e^1.5725=2216.59273<BR>\n" );
document.write( "2,216,593<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28300%2C300%2C-10%2C70%2C-300%2C3000%2C460e%5E%28.03145x%29%29 ALIGN=MIDDLE  ALT=\"graph%28300%2C300%2C-10%2C70%2C-300%2C3000%2C460e%5E%28.03145x%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );