document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=383502>Question 383502</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Students sit a statistics test and then are tested with equivalent tests, monthly after that. The average test result, T, after n months, was found to be given by T=17.4-4.6log(n+1). After how many months would the average mark be expected to be less than 12 marks?\r<BR>\n" );
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document.write( "The sales of a new electronic gadget are growing exponentially such that, 10 000 gadgets were sold in 2000 and 82 700 gadgets were sold in 2002. If this trend continues when will sales of the gadget reach over 500 000?\r<BR>\n" );
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document.write( "Please help Im so stuck and going bonkers!!!!! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #271542 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=271542\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Students sit a statistics test and then are tested with equivalent tests, monthly after that. The average test result, T, after n months, was found to be given by T=17.4-4.6log(n+1). After how many months would the average mark be expected to be less than 12 marks?<BR>\n" );
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document.write( "Solve 17.4-4.6log(n+1)< 12 for \"n\".<BR>\n" );
document.write( "4.6log(n+1) = 5.4<BR>\n" );
document.write( "log(n+1) = 1.173913<BR>\n" );
document.write( "n+1 = 10^1.173913<BR>\n" );
document.write( "n = 13.92 months<BR>\n" );
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document.write( "The sales of a new electronic gadget are growing exponentially such that, <BR>\n" );
document.write( "10 000 gadgets were sold in 2000 and 82,700 gadgets were sold in 2002. If this trend continues when will sales of the gadget reach over 500,000? <BR>\n" );
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document.write( "Form: y = ab^x<BR>\n" );
document.write( "Solve for a and b.<BR>\n" );
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document.write( "82700 = ab^2<BR>\n" );
document.write( "10000 = ab^0<BR>\n" );
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document.write( "a = 10000<BR>\n" );
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document.write( "b^2 = 82700/10000<BR>\n" );
document.write( "b^2 = 8.27<BR>\n" );
document.write( "b = 2.8757<BR>\n" );
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document.write( "Equation:<BR>\n" );
document.write( "y = 10,000*2.8757^x<BR>\n" );
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document.write( "Solve 10,000*2.8757^x > 500,000<BR>\n" );
document.write( "2.8757^x > 50<BR>\n" );
document.write( "x*log(2.8757) > log50<BR>\n" );
document.write( "x > 3.7035 years<BR>\n" );
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document.write( "Year 2000 + 3.7 = year 2004<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. <BR>\n" );
document.write( ". </SPAN>\n" );
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