document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=134870>Question 134870</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0030358299/algebrahomeworkh></A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> Iodine-131 is a radioactive material used to treat a certain types of cancer. Iodine-131 has half-life of 8 days, which means that it tkes 8 days for half of an initial sample to decay. The percent of radioactive material that remains after t days can be detemined from the expression 100(1/2)^t/h, where h is the half-life in days.\r<BR>\n" );
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document.write( "a.what percent of a sample of iodine-131 will remain after 20 days?\r<BR>\n" );
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document.write( "b.Another form of raioactive iodine used in cancer treatment is iodine-125. Iodine-125 has a half-life of 59 days. A hospital has 20 g of iodine-125 and 20 g of Iodine-131 left over from treating patients. How much more iodine-125 than iodine-131 will remain after a period of 30 days? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #98761 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=98761\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Iodine-131 is a radioactive material used to treat a certain types of cancer. Iodine-131 has half-life of 8 days, which means that it takes 8 days for half of an initial sample to decay. The percent of radioactive material that remains after t days can be determined from the expression 100(1/2)^t/h, where h is the half-life in days.<BR>\n" );
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document.write( "a.what percent of a sample of iodine-131 will remain after 20 days?<BR>\n" );
document.write( "A% = 100(1/2)^(20/8)<BR>\n" );
document.write( "A% = 100(1/2)^2.5<BR>\n" );
document.write( "A% = 100 * .1767767<BR>\n" );
document.write( "A% = 17.68 %<BR>\n" );
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document.write( "b. Another form of radioactive iodine used in cancer treatment is iodine-125. Iodine-125 has a half-life of 59 days. A hospital has 20 g of iodine-125 and 20 g of Iodine-131 left over from treating patients. How much more iodine-125 than iodine-131 will remain after a period of 30 days?<BR>\n" );
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document.write( "Find the amt of Iodine-125 will be left after 30 days<BR>\n" );
document.write( "I-125 = 20(1/2)^(30/59)<BR>\n" );
document.write( "I-125 = 20 * .2554<BR>\n" );
document.write( "I-125 = 5.08 g after 30 days<BR>\n" );
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document.write( "Find the amt of Iodine-131 will be left after 30 days<BR>\n" );
document.write( "I-131 = 20(1/2)^(30/8)<BR>\n" );
document.write( "I=131 = 20 * .0743<BR>\n" );
document.write( "I-131 = 1.49 g after 30 days<BR>\n" );
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document.write( "5.08 - 1.49 = 3.61 g more of the Iodine-125<BR>\n" );
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