document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=887629>Question 887629</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the numbered ball in a certain jar have an average of 12. if ball 28 is removed from the jar, then the average is decreased by 2. how many balls are there originally? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #536767 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=536767\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> not sure if this is right but i did get an answer.<BR>\n" );
document.write( "let's see if it makes any sense.<BR>\n" );
document.write( "s = sum of numbers on the balls in the jar.<BR>\n" );
document.write( "n = number of balls in the jar.<BR>\n" );
document.write( "s/n = 12\r<BR>\n" );
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document.write( "if the ball with the number 28 on it is removed from the jar, then the average is decreased by 2.<BR>\n" );
document.write( "s-28 = sum of numbers on the balls in the jar after the ball with number 28 on it has been removed.<BR>\n" );
document.write( "n-1 = number of balls in the jar after the ball with the number 28 on it has been removed.\r<BR>\n" );
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document.write( "you get:<BR>\n" );
document.write( "(s-28) / (n-1) = (12-2) which results in:<BR>\n" );
document.write( "(s-28) / (n-1) = 10\r<BR>\n" );
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document.write( "you have 2 equations to work with.<BR>\n" );
document.write( "they are:<BR>\n" );
document.write( "s/n = 12<BR>\n" );
document.write( "(s-28)/(n-1) = 10\r<BR>\n" );
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document.write( "in the first equation, solve for s to get s = 12*n\r<BR>\n" );
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document.write( "in the second equation, replace s with 12*n to get:<BR>\n" );
document.write( "(s-28)/(n-1) = 10 becomes:<BR>\n" );
document.write( "(12*n-28) / (n-1) = 10\r<BR>\n" );
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document.write( "multiply both sides of this equation by (n-1) to get:<BR>\n" );
document.write( "12*n-28 = 10*(n-1)<BR>\n" );
document.write( "simplify to get:<BR>\n" );
document.write( "12*n-28 = 10*n - 10\r<BR>\n" );
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document.write( "add 28 to both sides of this equation to get:<BR>\n" );
document.write( "12*n = 10*n - 10 + 28<BR>\n" );
document.write( "simplify to get:<BR>\n" );
document.write( "12*n = 10*n + 18<BR>\n" );
document.write( "subtract 10*n from both sides of this equation to get:<BR>\n" );
document.write( "2*n = 18<BR>\n" );
document.write( "divide both sides of this equation by 2 to get:<BR>\n" );
document.write( "n = 9\r<BR>\n" );
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document.write( "that should be your answer.\r<BR>\n" );
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document.write( "since s/n = 12 and n = 9, then s/9 = 12 which makes s = 12*9 = 108\r<BR>\n" );
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document.write( "the average is 108 / 9 = 12.\r<BR>\n" );
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document.write( "now take 28 away from the sum and take 1 away from n and you get s-28 = 80 and n-1 = 8.\r<BR>\n" );
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document.write( "the new average is 80/8 = 10\r<BR>\n" );
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document.write( "looks like the answer is correct as far as i can see.\r<BR>\n" );
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document.write( "there are 9 balls in the jar originally.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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