document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=253637>Question 253637</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A radioactive substance has an initial mass of 100 grams and its mass halves every 4 years. Write an expression that shows the number of grams remaining after x years.\r<BR>\n" );
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document.write( "I tried doing this problem by following this formula:<BR>\n" );
document.write( "initial mass times [1+ (r/n)]^nt\r<BR>\n" );
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document.write( "r= rate<BR>\n" );
document.write( "n= number of 'stuff' I think it is the number of time periods which the substance halves. It should be expressed by t/4.<BR>\n" );
document.write( "t= time\r<BR>\n" );
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document.write( "Since the problem is a decay model isn't the rate negative? So I believe it should be -0.5.\r<BR>\n" );
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document.write( "100 [1+((-0.5/(t/4))]^t/4*t<BR>\n" );
document.write( "I just get stuck here because it becomes very hairy and confusing...<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 #185997 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=185997\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A radioactive substance has an initial mass of 100 grams and its mass halves every 4 years. Write an expression that shows the number of grams remaining after x years. <BR>\n" );
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document.write( "A(t) = A(0)(1/2)^(t/4)<BR>\n" );
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document.write( "A(t) = 100(1/2)^(x/4)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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