document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=954560>Question 954560</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The half-life of radium is 1600 years. If 1000g are initially present, how much will remain after 3200 years? How long will it take to decay to 50g? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #583069 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39620)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><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=583069\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The first question is easily answered with no fancy calculations.  3200 years is TWO half-lives.  250 grams remain.  Continuing in half-lives, you can come near the number of years to reach 50 grams, but a computation using the decay model might be better.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k=4.33%2A10%5E%28-4%29 ALIGN=MIDDLE  ALT=\"k=4.33%2A10%5E%28-4%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "The decay formula will give <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=ln%28I%2Fy%29%2Fk ALIGN=MIDDLE  ALT=\"t=ln%28I%2Fy%29%2Fk\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28t%5B50g%5D=ln%281000%2F50%29%2F%280.000433%29%29 ALIGN=MIDDLE  ALT=\"highlight%28t%5B50g%5D=ln%281000%2F50%29%2F%280.000433%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "compute that, for years.\r<BR>\n" );
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document.write( "6900 years </SPAN>\n" );
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