document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1164626>Question 1164626</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The function f(x) = 800(.5)^ x/60 models the account in pounds of a particular radioactive material stored in a concrete vault, where X is the number of years since the material was put into the vault. Find the amount of radioactive material in the vault after 130 years. Round to the nearest whole number. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #789037 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=789037\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> this is f(x)=800*.5^(130/60)<BR>\n" );
document.write( "=178.18 pounds or 178 pounds.\r<BR>\n" );
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document.write( "check<BR>\n" );
document.write( "half-life is 60 years by the formula<BR>\n" );
document.write( "this is 2 half-lives and a little more which means that a little more than 3/4 of the material is gone<BR>\n" );
document.write( "(3/4) or 800 is 600, so there is a little less than 800-600 or 200 pounds left, which is consistent with the answer. </SPAN>\n" );
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