document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=548407>Question 548407</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The logistic growth function P(x)= 90/ 1+271e^(-.122x) models the percentage P(x), of Americans who are x years old and have some type of coronary heart disease. Use this function to find the age at which the percentage of Americans with some type of heart disease is 69%. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #356973 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=356973\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The logistic growth function P(x)= 90/ 1+271e^(-.122x) models the percentage P(x), of Americans who are x years old and have some type of coronary heart disease. Use this function to find the age at which the percentage of Americans with some type of heart disease is 69%.<BR>\n" );
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document.write( "69 = 90/[1+271e^(-0.122x)<BR>\n" );
document.write( "1+271e^(-0.122x) = 90/69 = 1.3043<BR>\n" );
document.write( "e^(-0.122x) = 0.3043/271<BR>\n" );
document.write( "Take the natural log:<BR>\n" );
document.write( "-0.122x = ln(0.3043/271) = -6.7917<BR>\n" );
document.write( "x = 55.67 years of age<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "=============== </SPAN>\n" );
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