document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=864218>Question 864218</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A certain radioactive isotope has a half life of approximately 850 years . How many years to the nearest year would be required for a given amount of this isotope to decay to 45% of that amount </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #520843 by </B><A HREF=/tutors/aboutme.mpl?userid=ewatrrr><B>ewatrrr(24785)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ewatrrr><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=ewatrrr><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=520843\">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=Q%28t%29+=+Q%5B0%5De%5E%28-kt%29+ ALIGN=MIDDLE  ALT=\"Q%28t%29+=+Q%5B0%5De%5E%28-kt%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  first find k<BR>\n" );
document.write( " <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28.5%29%2F%28-850%29 ALIGN=MIDDLE  ALT=\"ln%28.5%29%2F%28-850%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = k = .00082<BR>\n" );
document.write( "then find<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+ln%28.45%29%2F%28-.0008%29 ALIGN=MIDDLE  ALT=\"+ln%28.45%29%2F%28-.0008%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = t = 998 yrs </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );