document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=65624>Question 65624</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0130914657/algebrahomeworkh></A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> 10. The half-life of radioactive potassium is 1.3 billion years. If 10 grams is present now, how much will be present in 100 years? In 1000 years?\r<BR>\n" );
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document.write( "12.A fossilized leaf contains 70% of its normal  amount of carbon 14. How old is the fossil? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #46268 by </B><A HREF=/tutors/aboutme.mpl?userid=Nate><B>Nate(3500)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Nate><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=46268\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A = Pe^(rt)<BR>\n" );
document.write( "P/2 = Pe^(1,300,000,000r)<BR>\n" );
document.write( "1/2 = e^(1,300,000,000r)<BR>\n" );
document.write( "ln(0.5) = 1,300,000,000r<BR>\n" );
document.write( "ln(0.5)/1,300,000,000 = r<BR>\n" );
document.write( "r is about -5.33e-10<BR>\n" );
document.write( "A = 10e^(r*100)<BR>\n" );
document.write( "and<BR>\n" );
document.write( "A = 10e^(r*1000)<BR>\n" );
document.write( "I do not have a calculator with \"e\" right now.<BR>\n" );
document.write( "0.7P = Pe^(rt)<BR>\n" );
document.write( "0.7 = e^(rt)<BR>\n" );
document.write( "I need to know the rate .... </SPAN>\n" );
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