document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=111072>Question 111072</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This is not from a book, but I desperately need it answered in the next couple hours. I've tried all evening and cannot get the correct answer!  Help!\r<BR>\n" );
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document.write( "A radioactive element sodium-24 has a half-life of 14 hrs. and is used to help locate obstructions of blood flow.  A procedure requires 0.9 grams and is scheduled to take place in 43 hours.  The rate of decay of sodium-24 is 5%. <BR>\n" );
document.write( "What is the minimum amount of sodium-24 that must be on hand now?\r<BR>\n" );
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document.write( "At least ____ years.  (Answer should be accurate to two decimal places.)\r<BR>\n" );
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document.write( "Thanks! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #81056 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=81056\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 43 hrs is slightly more than 3 half-lives, so you will need slightly more than .9*2^3 g\r<BR>\n" );
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document.write( "let x= amount needed ___ .9=x(.5^(43/14)) ___ .9(2^(43/14))=x </SPAN>\n" );
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