document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=808437>Question 808437</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A person's average was 64%. One the next test he got 68%. This raised his average to 65%. The next test, his average improved by 1% again. What did he get on the last test?<BR>\n" );
document.write( "I thought of doing trial and error: I tried adding everything and dividing by the amount plus the number of extra 64s, but it took too long. I still don't know what the answer is. Please help me! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #487006 by </B><A HREF=/tutors/aboutme.mpl?userid=KMST><B>KMST(5328)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=KMST><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=KMST><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=487006\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> We assume the 64% average was the average of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n ALIGN=MIDDLE  ALT=\"n\"   DISABLED_style= \"max-width:90%; height:auto;\" > tests.<BR>\n" );
document.write( "THe sum of the grades of those <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n ALIGN=MIDDLE  ALT=\"n\"   DISABLED_style= \"max-width:90%; height:auto;\" > tests was<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=64n ALIGN=MIDDLE  ALT=\"64n\"   DISABLED_style= \"max-width:90%; height:auto;\" > .<BR>\n" );
document.write( "When the next test grade was 68%, the sum of the grades of all the tests was<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=64n%2B68 ALIGN=MIDDLE  ALT=\"64n%2B68\"   DISABLED_style= \"max-width:90%; height:auto;\" > , and since there were <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%2B1 ALIGN=MIDDLE  ALT=\"n%2B1\"   DISABLED_style= \"max-width:90%; height:auto;\" > tests by then,<BR>\n" );
document.write( "the average was <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2864n%2B68%29%2F%28n%2B1%29 ALIGN=MIDDLE  ALT=\"%2864n%2B68%29%2F%28n%2B1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > .<BR>\n" );
document.write( "We are told that average was 65%, so<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2864n%2B68%29%2F%28n%2B1%29=65 ALIGN=MIDDLE  ALT=\"%2864n%2B68%29%2F%28n%2B1%29=65\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=64n%2B68=65%28n%2B1%29 ALIGN=MIDDLE  ALT=\"64n%2B68=65%28n%2B1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=64n%2B68=65n%2B65 ALIGN=MIDDLE  ALT=\"64n%2B68=65n%2B65\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=68-65=65n-64n ALIGN=MIDDLE  ALT=\"68-65=65n-64n\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3=n ALIGN=MIDDLE  ALT=\"3=n\"   DISABLED_style= \"max-width:90%; height:auto;\" > .<BR>\n" );
document.write( "So the average was 64% after 3 tests and 65% after 4 tests.<BR>\n" );
document.write( "After the 5th test, the average was 1% higher (than 65%),<BR>\n" );
document.write( "so it was 65% + 1% = 66%.<BR>\n" );
document.write( "The sum of the first 4 tests was <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=65%2A4=260 ALIGN=MIDDLE  ALT=\"65%2A4=260\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "With a percentage score of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x ALIGN=MIDDLE  ALT=\"x\"   DISABLED_style= \"max-width:90%; height:auto;\" > on the fifth test,<BR>\n" );
document.write( "the sum of the grades on the first 5 tests is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=260%2Bx ALIGN=MIDDLE  ALT=\"260%2Bx\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The average for the first 5 tests can be calculated as<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28260%2Bx%29%2F5 ALIGN=MIDDLE  ALT=\"%28260%2Bx%29%2F5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and since the average is 66%,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28260%2Bx%29%2F5=66 ALIGN=MIDDLE  ALT=\"%28260%2Bx%29%2F5=66\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=260%2Bx=66%2A5 ALIGN=MIDDLE  ALT=\"260%2Bx=66%2A5\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=260%2Bx=330 ALIGN=MIDDLE  ALT=\"260%2Bx=330\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=330-260 ALIGN=MIDDLE  ALT=\"x=330-260\"   DISABLED_style= \"max-width:90%; height:auto;\" > --> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28x=70%29 ALIGN=MIDDLE  ALT=\"highlight%28x=70%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );