document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=805161>Question 805161</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The Half-Life of palladium-100 is 4 days.  After 20 days a sample has been reduced to a mass of .375 grams.\r<BR>\n" );
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document.write( "What was the initial mass of the sample?\r<BR>\n" );
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document.write( "What is the mass after 3 days?\r<BR>\n" );
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document.write( "After how many days will only .15 g remain?\r<BR>\n" );
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document.write( "Thank you so much!! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #485100 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=485100\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The Half-Life of palladium-100 is 4 days.<BR>\n" );
document.write( " After 20 days a sample has been reduced to a mass of .375 grams.<BR>\n" );
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document.write( "Using the formula: A = Ao*2^(-t/h); where:<BR>\n" );
document.write( "A = the resulting amt after t time<BR>\n" );
document.write( "Ao = initial amt (t=0)<BR>\n" );
document.write( "t = time of decay<BR>\n" );
document.write( "h = half-life of the substance<BR>\n" );
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document.write( "What was the initial mass of the sample?<BR>\n" );
document.write( "Ao*2^(-20/4) = .375<BR>\n" );
document.write( "Ao*2^(-5) = .375<BR>\n" );
document.write( "Ao = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F2%5E5 ALIGN=MIDDLE  ALT=\"1%2F2%5E5\"   DISABLED_style= \"max-width:90%; height:auto;\" > = .375<BR>\n" );
document.write( "Ao = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F32 ALIGN=MIDDLE  ALT=\"1%2F32\"   DISABLED_style= \"max-width:90%; height:auto;\" > = .375<BR>\n" );
document.write( "Ao = .375 * 32<BR>\n" );
document.write( "Ao = 12 grams is the initial amt<BR>\n" );
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document.write( "What is the mass after 3 days?<BR>\n" );
document.write( "A = 12*2^(-3/4)<BR>\n" );
document.write( "A = 12*.5946<BR>\n" );
document.write( "A = 7.135 grams after 3 days<BR>\n" );
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document.write( "After how many days will only .15 g remain? <BR>\n" );
document.write( "12*2(-t/4) = .15<BR>\n" );
document.write( "2^(-t/4) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=.15%2F12 ALIGN=MIDDLE  ALT=\".15%2F12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "2^(-t/4) = .0125<BR>\n" );
document.write( "Using nat logs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-t%2F4 ALIGN=MIDDLE  ALT=\"-t%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28.0125%29%2Fln%282%29 ALIGN=MIDDLE  ALT=\"ln%28.0125%29%2Fln%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%2F4 ALIGN=MIDDLE  ALT=\"-t%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" > = -6.322<BR>\n" );
document.write( "t = -4 * -6.322<BR>\n" );
document.write( "t = +25.3 days for only .15 gr to remain </SPAN>\n" );
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