document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=641182>Question 641182</A>: <I><SPAN STYLE=\"word-break: break-all;\"> bill's scores on his first four science tests are 86,,90,84,and 91.what test score must bill earn on the fifth test so that his average (mean) will be exactly 88? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #403575 by </B><A HREF=/tutors/aboutme.mpl?userid=josh_jordan><B>josh_jordan(263)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josh_jordan><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=josh_jordan><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=403575\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> To solve, we first need to know how to find the average of a group of numbers.  To find the average of a group of numbers, you add all the numbers together and divide that answer by the number of numbers you have.  For instance, to find the average of 1, 2, 3, 4 and 5, we would add all the numbers together, which would equal 15.  We would then divide that number by 5, because there are 5 numbers total:  15/5 = 3.  So the average is 3.  \r<BR>\n" );
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document.write( "Now, to find the average in your problem, we need to look at what we know:\r<BR>\n" );
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document.write( "We know there are a total of 5 tests<BR>\n" );
document.write( "We know 4 of the scores<BR>\n" );
document.write( "The average of all 5 tests is 88\r<BR>\n" );
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document.write( "In other words:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2886%2B90%2B84%2B91%2Bx%29%2F5+=+88 ALIGN=MIDDLE  ALT=\"%2886%2B90%2B84%2B91%2Bx%29%2F5+=+88\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "If we multiply both sides of this equation by 5, we will get rid of the<BR>\n" );
document.write( "fraction, and leave us with:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=86%2B90%2B84%2B91%2Bx+=+88%2A5 ALIGN=MIDDLE  ALT=\"86%2B90%2B84%2B91%2Bx+=+88%2A5\"   DISABLED_style= \"max-width:90%; height:auto;\" > =\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=351%2Bx=440 ALIGN=MIDDLE  ALT=\"351%2Bx=440\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Finally, if we subtract 351 from both sides, we will be left with what x equals, which will be our 5th test score:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=351-351%2Bx=440-351 ALIGN=MIDDLE  ALT=\"351-351%2Bx=440-351\"   DISABLED_style= \"max-width:90%; height:auto;\" > =<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+89 ALIGN=MIDDLE  ALT=\"x+=+89\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "FINAL ANSWER:  Bill must earn an 89 on his fifth test<BR>\n" );
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