document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=848734>Question 848734</A>: <I><SPAN STYLE=\"word-break: break-all;\"> At the beginning of an experiment, a scientist has 224 grams of radioactive goo. After 270 minutes, her sample has decayed to 14 grams. <BR>\n" );
document.write( "1)What is the half-life of the goo in minutes? <BR>\n" );
document.write( "2)Find a formula for G(t), the amount of goo remaining at time t.\r<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 #511254 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=511254\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  At the beginning of an experiment, a scientist has 224 grams of radioactive goo. After 270 minutes, her sample has decayed to 14 grams.<BR>\n" );
document.write( "A(t) = ab^t<BR>\n" );
document.write( "14 = 224*b^270<BR>\n" );
document.write( "0.0625 = b^270<BR>\n" );
document.write( "b = 0.0625^(1/270)<BR>\n" );
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document.write( "1)What is the half-life of the goo in minutes?<BR>\n" );
document.write( "Solve 0.0625^(t/270) = 1/2<BR>\n" );
document.write( "(t/270)log(0.0625) = log(0.5)<BR>\n" );
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document.write( "t/270 = 0.25<BR>\n" );
document.write( "t = 67.5 minutes (that is the half-life)<BR>\n" );
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document.write( "2)Find a formula for G(t), the amount of goo remaining at time t. <BR>\n" );
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document.write( "A(t) = 224*0.0625^(t/270)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
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