document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=416076>Question 416076</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The half-life of strontium-90 is 28 years. How long will it take a 72 mg sample to decay to a mass of 18 mg?<BR>\n" );
document.write( "Your answer is years.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #291597 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><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=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=291597\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> For this problem, there is no need to use logarithms since it decays from 72 mg to 18 mg (one-fourth of the original amount). Hence, exactly two half-lives are required, so it would take 56 years. </SPAN>\n" );
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