document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=857775>Question 857775</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The radioactive isotope you discovered at 8 am weighed 75 mg. At 3 pm it measured only 0.009 grams.  Rounded to the nearest whole minute, what is its half life? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #516825 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39618)</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=516825\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <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;\" >, I is initial amount, A is final amount after time t.\r<BR>\n" );
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document.write( "FIND k<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28A%29=ln%28I%29-kt ALIGN=MIDDLE  ALT=\"ln%28A%29=ln%28I%29-kt\"   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%28A%29-ln%28I%29 ALIGN=MIDDLE  ALT=\"-kt=ln%28A%29-ln%28I%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%28ln%28I%29-ln%28A%29%29 ALIGN=MIDDLE  ALT=\"k=%281%2Ft%29%28ln%28I%29-ln%28A%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=%281%2Ft%29ln%28I%2FA%29 ALIGN=MIDDLE  ALT=\"k=%281%2Ft%29ln%28I%2FA%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%2F7%29ln%2875%2F0.009%29 ALIGN=MIDDLE  ALT=\"k=%281%2F7%29ln%2875%2F0.009%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28k=1.29%29 ALIGN=MIDDLE  ALT=\"highlight%28k=1.29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "USE k TO FIND HALF-LIFE<BR>\n" );
document.write( "Decay equation is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28A=Ie%5E%28-1.29t%29%29 ALIGN=MIDDLE  ALT=\"highlight_green%28A=Ie%5E%28-1.29t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "Let A=1/2 and let I=1.<BR>\n" );
document.write( "Solve for t. </SPAN>\n" );
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