document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=933433>Question 933433</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Sodium-24 is used for medical purposes. The half-life of sodium-24 is 14.9 h. A hospital buys 480 mg. After how long will 3.75mg remain?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #566803 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=566803\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The question description seems impractical.  Is  14.9 hours too short a time to purchase the expected 480 miligrams?  \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=Ie%5E%28-kt%29 ALIGN=MIDDLE  ALT=\"A=Ie%5E%28-kt%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281%2F2%29=1%2Ae%5E%28-kt%29 ALIGN=MIDDLE  ALT=\"%281%2F2%29=1%2Ae%5E%28-kt%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%281%2F2%29=ln%281%29-kt%2Aln%28e%29 ALIGN=MIDDLE  ALT=\"ln%281%2F2%29=ln%281%29-kt%2Aln%28e%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-kt=ln%281%2F2%29 ALIGN=MIDDLE  ALT=\"-kt=ln%281%2F2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k=-%281%2Ft%29ln%281%2F2%29 ALIGN=MIDDLE  ALT=\"k=-%281%2Ft%29ln%281%2F2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k=-%281%2Ft%29%28-ln%282%29%29 ALIGN=MIDDLE  ALT=\"k=-%281%2Ft%29%28-ln%282%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k=ln%282%29%2Ft ALIGN=MIDDLE  ALT=\"k=ln%282%29%2Ft\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28k=ln%282%29%2F14.9%29 ALIGN=MIDDLE  ALT=\"highlight_green%28k=ln%282%29%2F14.9%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "The model becomes <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28A=480%2Ae%5E%28-0.4652t%29%29 ALIGN=MIDDLE  ALT=\"highlight%28A=480%2Ae%5E%28-0.4652t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "You need a solution for t.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28A%29=ln%28480%29%2Bln%28e%5E%28-0.04652t%29%29 ALIGN=MIDDLE  ALT=\"ln%28A%29=ln%28480%29%2Bln%28e%5E%28-0.04652t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28A%29-ln%28480%29=-0.04652t ALIGN=MIDDLE  ALT=\"ln%28A%29-ln%28480%29=-0.04652t\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28480%29-ln%28A%29=0.04652t ALIGN=MIDDLE  ALT=\"ln%28480%29-ln%28A%29=0.04652t\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28t=%281%2F0.04652%29ln%28480%2FA%29%29 ALIGN=MIDDLE  ALT=\"highlight_green%28t=%281%2F0.04652%29ln%28480%2FA%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Let A=3.75 and evaluate t.\r<BR>\n" );
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document.write( "t=104 hours.<BR>\n" );
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document.write( "4 days 8 hours 30 minutes\r<BR>\n" );
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document.write( "CHECK:  This should be 7 periods of halflife time.<BR>\n" );
document.write( "14.9*7=104.3, checks. </SPAN>\n" );
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