document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=866480>Question 866480</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Archeologists can use the known decay rate of Carbon- 14 to estimate the age of organic objects. Suppose Illinois Jones has discovered a wooden spear in a cave. If the wood contains 12% of it s original amount of Carbon- 14, approximately how old is the spear? The half-life of Carbon-14 is 5730. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #522410 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=522410\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Archeologists can use the known decay rate of Carbon- 14 to estimate the age of organic objects.<BR>\n" );
document.write( " If the wood contains 12% of it s original amount of Carbon- 14, approximately how old is the spear?<BR>\n" );
document.write( " The half-life of Carbon-14 is 5730.<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Use the radioactive decay formula: A = Ao*2^(-t/h); where:<BR>\n" );
document.write( "A = remaining amt after t time<BR>\n" );
document.write( "Ao = initial amt<BR>\n" );
document.write( "t = time of decay<BR>\n" );
document.write( "h = half-life of substance<BR>\n" );
document.write( ":<BR>\n" );
document.write( "let initial amt = 1, then remaining amt = .12<BR>\n" );
document.write( "1*2^(-t/5730) = .12<BR>\n" );
document.write( "using 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;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=log%28.12%29%2Flog%282%29 ALIGN=MIDDLE  ALT=\"log%28.12%29%2Flog%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;\" > = -3.05889<BR>\n" );
document.write( "t = -3.05889 * 5730<BR>\n" );
document.write( "t = 17,527 yrs is the age of the wood </SPAN>\n" );
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