document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1176907>Question 1176907</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A lawyer has determined that the number of people P(t) in a city of 1.9 million people who have been exposed to a news item after t days is given by the function<BR>\n" );
document.write( "P(t) = 1,900,000(1 − e−0.03t).<BR>\n" );
document.write( "(a) How many days after a major crime has been reported has 20% of the population heard of the crime? (Round your answer to the nearest day.) \r<BR>\n" );
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document.write( "(b) A defense lawyer knows it will be difficult to pick an unbiased jury after 80% of the population has heard of the crime. After how many days will 80% of the population have heard of the crime? (Round your answer to the nearest day.)  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #805061 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=805061\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 380000=1900000(1-e^(-0.03t))<BR>\n" );
document.write( "0.2=1-e^(-0.03t))<BR>\n" );
document.write( "-0.8=-e^(-0.03t)<BR>\n" );
document.write( "change both signs and take ln of both sides<BR>\n" );
document.write( "-0.2231=-0.03t<BR>\n" );
document.write( "t=7.4 days or 7 days<BR>\n" );
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document.write( "for 80%<BR>\n" );
document.write( "0.2=e^(-0.03t)<BR>\n" );
document.write( "-1.61=-0.03t<BR>\n" );
document.write( "t=54 days<BR>\n" );
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