document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=144265>Question 144265</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A certain radioactive isotope decays at a rate of 0.1% annually. Determine the half-life of this isotope, to the nearest year. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #105056 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=105056\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A certain radioactive isotope decays at a rate of 0.1% annually. Determine the half-life of this isotope, to the nearest year.<BR>\n" );
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document.write( "A(t) = Ao(1-0.001)^t<BR>\n" );
document.write( "(1/2)Ao = Ao(0.999)^t<BR>\n" );
document.write( "0.999^t = (1/2)<BR>\n" );
document.write( "t = [log(1/2) / log(0.999)]\r<BR>\n" );
document.write( "\n" );
document.write( "t = 692.80 years<BR>\n" );
document.write( "====================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );