document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1025723>Question 1025723</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A pharmaceutical company is developing a new drug. The level of the new drug reduces by 28% each hour after it is taken by the patient. It is recommended that one tablet is taken initially and a second tablet is taken when the level of the drug in the first tablet has reduced by half. The pharmaceutical company would like to put a recommendation on the packet about how often one tablet should be taken. Investigate the time it takes for the level of this drug to reduce by half and make a recommendation to the company about how often one tablet should be taken. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #641026 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=641026\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the drug reduces by 28% each hour.\r<BR>\n" );
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document.write( "level of the drug after 1 hour is therefore 1 - .28 * 1 = .72\r<BR>\n" );
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document.write( "you want to find when the drug reaches .5\r<BR>\n" );
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document.write( "formula to use would be .5 = .72 ^ n\r<BR>\n" );
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document.write( "n equals the number of hours.\r<BR>\n" );
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document.write( "take the log of both sides of this equation to get log(.5) = log(.72^n).\r<BR>\n" );
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document.write( "since log(.72^n) is equal to n * log(.72), the equation becomes log(.5) = n * log(.72).\r<BR>\n" );
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document.write( "divide both sides of this equation by log(.72) to get n = log(.5) / log(.72).\r<BR>\n" );
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document.write( "this results in n = 2.110010956 hours.\r<BR>\n" );
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document.write( "since 2.11 hours is close to 2 hours, you would probably recommend the pill be taken every 2 hours.\r<BR>\n" );
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document.write( "in 2 hours, the level of the pill would be .72^2 = 51.84% of its original strength.\r<BR>\n" );
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document.write( "that's pretty close and much easier to remember than 2 hours and 6 or 7 minutes.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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