document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1081990>Question 1081990</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Smoking.  the percentage of smokers who receive telephone counseling and successfully quit smoking for t months is given by     P(t)=21.4(o.914)^t\r<BR>\n" );
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document.write( "In what month will 15% of those who quit and used telephone counseling still be smoke free?\r<BR>\n" );
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document.write( "In what month will 5% of those who quit and used telephone counseling still be smoke free? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #696055 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=696055\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 15=21.4(0.914)^t<BR>\n" );
document.write( "0.7009=0.914^t<BR>\n" );
document.write( "ln both sides<BR>\n" );
document.write( "-0.3553=t *-0.0899, that is the ln of 0.914<BR>\n" );
document.write( "t=3.95, in the fourth month. The closest is four months.<BR>\n" );
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document.write( "5/21.4, ln of both sides and divide out the constant on the right side<BR>\n" );
document.write( "-1.453/-0.0899=t=16.17 months.  After 16 months. </SPAN>\n" );
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