document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=753693>Question 753693</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Students in an english class took a final exam. They took quivalent forms of the exam at monthly intervals thereafter. The average score S(t), in percent, after t months was found to be given by:\r<BR>\n" );
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document.write( "                    S(t) = 68-20 log (t + 1),t > or = to 0.\r<BR>\n" );
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document.write( "1.What is the average score when they initially took the test, t=0?\r<BR>\n" );
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document.write( "2.What is the average score after 14 months?\r<BR>\n" );
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document.write( "3.After what time t was the average score of 40%? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #458533 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=458533\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Students in an english class took a final exam. They took quivalent forms of the exam at monthly intervals thereafter. The average score S(t), in percent, after t months was found to be given by: <BR>\n" );
document.write( "S(t) = 68-20 log (t + 1),t > or = to 0. <BR>\n" );
document.write( "1.What is the average score when they initially took the test, t=0?<BR>\n" );
document.write( "S(0) = 68-20*log(1) = 68-20*0 = 68<BR>\n" );
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document.write( "2.What is the average score after 14 months?<BR>\n" );
document.write( "S(14) = 68-20*log(15) = 68-23.52 = 44.48<BR>\n" );
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document.write( "3.After what time t was the average score of 40%?<BR>\n" );
document.write( "40 = 68-20*log(t+1)<BR>\n" );
document.write( "20*log(t+1) = 68-40<BR>\n" );
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document.write( "20*log(t+1) = 28<BR>\n" );
document.write( "log(t+1) = 1.4<BR>\n" );
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document.write( "t+1 = 10^1.4 = 25.12<BR>\n" );
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document.write( "t = 24.12<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "=====================<BR>\n" );
document.write( " </SPAN>\n" );
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