document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=747823>Question 747823</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The average, or mean, of your last three math tests is 84%. On the first two tests you earned an 80% and an 87%. What did you earn on the third math test?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #455171 by </B><A HREF=/tutors/aboutme.mpl?userid=FrankM><B>FrankM(1040)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=FrankM><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=FrankM><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=455171\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> To fins the average we add N numbers and divide by N. Here, N =3\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28X%2B80%2B87%29%2F3=84 ALIGN=MIDDLE  ALT=\"%28X%2B80%2B87%29%2F3=84\"   DISABLED_style= \"max-width:90%; height:auto;\" >  \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28X%2B80%2B87%29=%2884%2A3%29 ALIGN=MIDDLE  ALT=\"%28X%2B80%2B87%29=%2884%2A3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >  Multiply both sides by 3 to cancel the denominator for first expression.\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28X%2B80%2B87%29=252 ALIGN=MIDDLE  ALT=\"%28X%2B80%2B87%29=252\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X=85 ALIGN=MIDDLE  ALT=\"X=85\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Note - 80 is the average -4, 87 is the average +3. The missing number must be the average +1, so the differences to the average cancel to zero. This is a shortcut that avoids any multiplying, and can help you solve this type of short problem on your fingers. \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );