document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=608430>Question 608430</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I would like to know how to find the average of 4 numbers when only 3 are given<BR>\n" );
document.write( "here's the question (I don't want the answer just to know how to do it);         A student has earned scores of 87, 81, and 88 on the first 3 of 4 tests. If the student wants an average (arithmetic mean) of exactly 87, what score must she earn on the fourth test? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #383185 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=383185\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> here's the question (I don't want the answer just to know how to do it); A student has earned scores of 87, 81, and 88 on the first 3 of 4 tests. If the student wants an average (arithmetic mean) of exactly 87, what score must she earn on the fourth test?<BR>\n" );
document.write( "Let x = score of fourth test<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(87+81+88+x)/4 = 87<BR>\n" );
document.write( "(256+x)/4 = 87<BR>\n" );
document.write( "multiplying both sides by 4:<BR>\n" );
document.write( "256+x = 348<BR>\n" );
document.write( "x = 348-256<BR>\n" );
document.write( "x = 92<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );