document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1151005>Question 1151005</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In the formula A = I^ekt, A is the amount of radioactive material remaining from an initial amount I at a given time t and k is a negative constant determined by the nature of the material. A certain radioactive isotope has a half-life of approximately 950 years. How many years would be required for a given amount of this isotope to decay 20% of that amount? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #772583 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39617)</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=772583\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Formula should be A=Ie^(kt), assuming k is negative.\r<BR>\n" );
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document.write( "First part, given half life 950 years<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F2=e%5E%28950k%29 ALIGN=MIDDLE  ALT=\"1%2F2=e%5E%28950k%29\"   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=ln%281%2F2%29=950%2Ak ALIGN=MIDDLE  ALT=\"ln%281%2F2%29=950%2Ak\"   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=k=ln%281%2F2%29%2F950 ALIGN=MIDDLE  ALT=\"k=ln%281%2F2%29%2F950\"   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=k=-ln%282%29%2F950 ALIGN=MIDDLE  ALT=\"k=-ln%282%29%2F950\"   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=k=-0.0007296 ALIGN=MIDDLE  ALT=\"k=-0.0007296\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".\r<BR>\n" );
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document.write( ". </SPAN>\n" );
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