document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1086775>Question 1086775</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the math class has 4 exams. Each exam is out of 100 possible points. jackie got 67, 84, and 78. jackie wants to get at least a B.for the class, what score should she get on her last exam </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #701007 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=701007\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=\"black\" face=\"times\" size=\"3\">Exam Scores = {67,84,7,x} where x is a real number and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0+%3C=+x+%3C=+100 ALIGN=MIDDLE  ALT=\"0+%3C=+x+%3C=+100\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Sum of the scores = S = 67+84+78+x = 229+x<BR>\n" );
document.write( "sample size = n = 4<BR>\n" );
document.write( "Average = A = (sum of scores)/(sample size) = S/n = (229+x)/4\r<BR>\n" );
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document.write( "We want the average to be a B or higher. I'm assuming the grade \"B\" corresponds to a score of 80, which you could argue is a B- but I'm going to ignore the plus/minus for the letter grades. \r<BR>\n" );
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document.write( "So,<BR>\n" );
document.write( "A > 80<BR>\n" );
document.write( "(229+x)/4 > 80<BR>\n" );
document.write( "4*(229+x)/4 > 4*80<BR>\n" );
document.write( "229+x > 320<BR>\n" );
document.write( "229+x-229 > 320-229<BR>\n" );
document.write( "x > 91<BR>\n" );
document.write( "So you need to get a score of 91 to get an overall average of 80<BR>\n" );
document.write( "If you score higher than 91, then the average will be larger than 80\r<BR>\n" );
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document.write( "If you place a B grade at something like 85, then <BR>\n" );
document.write( "A > 80<BR>\n" );
document.write( "(229+x)/4 > 85<BR>\n" );
document.write( "4*(229+x)/4 > 4*85<BR>\n" );
document.write( "229+x > 340<BR>\n" );
document.write( "229+x-229 > 340-229<BR>\n" );
document.write( "x > 111<BR>\n" );
document.write( "which is impossible to accomplish (x maxes out at 100)\r<BR>\n" );
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document.write( "You're probably wondering: \"What is the highest average possible?\". That happens when x = 100. Let's plug that into the equation below to find A<BR>\n" );
document.write( "A = (229+x)/4<BR>\n" );
document.write( "A = (229+100)/4<BR>\n" );
document.write( "A = 82.25\r<BR>\n" );
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document.write( "So the best average possible is 82.25% or 82% if you round to the nearest whole percent. </font> </SPAN>\n" );
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