document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=792092>Question 792092</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Wood deposits recovered from an archaeological site contain 36% of the C-14 they originally contained. How long ago did the tree from which the wood was obtained die? (Round your answer to the nearest whole number.)<BR>\n" );
document.write( "________yr </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #479899 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=479899\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Wood deposits recovered from an archaeological site contain 36% of the C-14 they originally contained.<BR>\n" );
document.write( " How long ago did the tree from which the wood was obtained die?<BR>\n" );
document.write( " (Round your answer to the nearest whole number.)<BR>\n" );
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document.write( "The radio-active decay formula: A = Ao*2^(-t/h), Where:<BR>\n" );
document.write( "A = resulting amt after t time<BR>\n" );
document.write( "Ao = initial amt (t-0)<BR>\n" );
document.write( "t = time in yrs<BR>\n" );
document.write( "h = half-life of substance (carbon 14 half-life is 5730 yrs)<BR>\n" );
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document.write( "Let initial amt = 1, then resulting amt = .36<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%5E%28-t%2F5730%29 ALIGN=MIDDLE  ALT=\"2%5E%28-t%2F5730%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = .36<BR>\n" );
document.write( "Using nat logs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-t%2F5730 ALIGN=MIDDLE  ALT=\"-t%2F5730\"   DISABLED_style= \"max-width:90%; height:auto;\" >*ln(2) = ln(.36)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-t%2F5730 ALIGN=MIDDLE  ALT=\"-t%2F5730\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28.36%29%2Fln%282%29 ALIGN=MIDDLE  ALT=\"ln%28.36%29%2Fln%282%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-t%2F5730 ALIGN=MIDDLE  ALT=\"-t%2F5730\"   DISABLED_style= \"max-width:90%; height:auto;\" > = -1.47393<BR>\n" );
document.write( "t = -5730 * -1.47393<BR>\n" );
document.write( "t = 8,446 yrs ago </SPAN>\n" );
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