document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1203583>Question 1203583</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Richie's average on his math test was 64%. On the next test he had a mark of 76%, and this raised his overall average to 67%. When he wrote the next test after this his average improved again by 1%. What mark did he get on the last test?\r<BR>\n" );
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document.write( "A) 68% B) 69% C) 70% D) 71% E) 72% </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #839253 by </B><A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><B>math_tutor2020(3817)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><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=839253\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "x% = score on the last test<BR>\n" );
document.write( "n = number of math tests he has taken before the 76% and x% scores\r<BR>\n" );
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document.write( "(sum of test scores)/(number of tests) = average score<BR>\n" );
document.write( "(sum of test scores)/n = 64<BR>\n" );
document.write( "sum of test scores = 64n\r<BR>\n" );
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document.write( "64n+76 = updated sum after taking another test<BR>\n" );
document.write( "(64n+76)/(n+1) = updated average<BR>\n" );
document.write( "(64n+76)/(n+1) = 67<BR>\n" );
document.write( "64n+76 = 67(n+1)<BR>\n" );
document.write( "64n+76 = 67n+67<BR>\n" );
document.write( "64n-67n = 67-76<BR>\n" );
document.write( "-3n = -9<BR>\n" );
document.write( "n = -9/(-3)<BR>\n" );
document.write( "n = 3<BR>\n" );
document.write( "Richie has taken 3 tests so far to get an average of 64%<BR>\n" );
document.write( "The fourth test score is 76% which moves the average to 67%\r<BR>\n" );
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document.write( "The 5th test score is unknown, which we call x.<BR>\n" );
document.write( "What we do know is that taking this 5th test will move the average to 68% \r<BR>\n" );
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document.write( "(64n+76+x)/5 = 68<BR>\n" );
document.write( "(64*3+76+x)/5 = 68<BR>\n" );
document.write( "(268+x)/5 = 68<BR>\n" );
document.write( "268+x = 5*68<BR>\n" );
document.write( "268+x = 340<BR>\n" );
document.write( "x = 340-268<BR>\n" );
document.write( "x = 72\r<BR>\n" );
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document.write( "Answer:  <font color=red>72%</font><BR>\n" );
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