document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=359507>Question 359507</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the mean of a set of numbers is 120. if one number is increased by 300, the mean increases to 135. how many numbers are in the set? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #256502 by </B><A HREF=/tutors/aboutme.mpl?userid=neatmath><B>neatmath(302)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=neatmath><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=neatmath><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=256502\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You have two unknown numbers in this case. <br>\r<BR>\n" );
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document.write( "The mean of a set of numbers is simply the sum total of the set values divided by the number of values in the set.<br>\r<BR>\n" );
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document.write( "We will let t be the sum total of the values, and n be the number of values in the set.<br>\r<BR>\n" );
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document.write( "So, the mean of a set should be <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%2Fn=mean ALIGN=MIDDLE  ALT=\"t%2Fn=mean\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br>\r<BR>\n" );
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document.write( "So, in this case, we are given <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%2Fn=120 ALIGN=MIDDLE  ALT=\"t%2Fn=120\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28t%2B300%29%2Fn=135 ALIGN=MIDDLE  ALT=\"%28t%2B300%29%2Fn=135\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br>\r<BR>\n" );
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document.write( "We just need to solve this system of equations to find t and n, so:<br>\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=120%2An ALIGN=MIDDLE  ALT=\"t=120%2An\"   DISABLED_style= \"max-width:90%; height:auto;\" > solve for t and plug this into the 2nd equation:<br>\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28120%2An%2B300%29%2Fn=135 ALIGN=MIDDLE  ALT=\"%28120%2An%2B300%29%2Fn=135\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br>\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=120%2An%2B300=135n ALIGN=MIDDLE  ALT=\"120%2An%2B300=135n\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br>\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=300=135n-120n ALIGN=MIDDLE  ALT=\"300=135n-120n\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br>\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=300=15n ALIGN=MIDDLE  ALT=\"300=15n\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br>\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n=20 ALIGN=MIDDLE  ALT=\"n=20\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br>\r<BR>\n" );
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document.write( "Thus, there are 20 numbers in the set!<br>\r<BR>\n" );
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document.write( "You can then use n=20 to find t, but in this case it is not necessary.<br>\r<BR>\n" );
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document.write( "I hope this helps!<br> </SPAN>\n" );
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