document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1004575>Question 1004575</A>: <I><SPAN STYLE=\"word-break: break-all;\"> At the beginning of an experiment, a scientist has 256 grams of radioactive goo. After 105 minutes, her sample has decayed to 16 grams. \r<BR>\n" );
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document.write( "What is the half-life of the goo in minutes?  <BR>\n" );
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document.write( "Find a formula for G(t), the amount of goo remaining at time t. G(t) = <BR>\n" );
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document.write( "How many grams of goo will remain after 17 minutes? <BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #621046 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=621046\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Our half-life formula is<BR>\n" );
document.write( "G(t) = Ao * (1/2)^(t/h), where h is the half-life and A0 is the beginning amount<BR>\n" );
document.write( "16 = 256 * (1/2)^(105/h)<BR>\n" );
document.write( "1/16 = (1/2)^(105/h)<BR>\n" );
document.write( "use definition of logarithm<BR>\n" );
document.write( "105/h = log (base 1/2) of 1/16<BR>\n" );
document.write( "105/h = 4<BR>\n" );
document.write( "h = 105/4 = 26.25 minutes<BR>\n" );
document.write( "half-life is 26.25 minutes<BR>\n" );
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document.write( "we use our formula for t = 17<BR>\n" );
document.write( "G(17) = 256 * (1/2)^(17/26.25)<BR>\n" );
document.write( "G(17) = 163.413226968 approx 163.4<BR>\n" );
document.write( "There is 163.4 grams of goo after 17 minutes<BR>\n" );
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