document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=888558>Question 888558</A>: <I><SPAN STYLE=\"word-break: break-all;\"> in a group of 40 workers, the average (arithmetic mean) salary is $70 a day per worker. If some of the workers earn $65 a day and all the rest earn $90 a  day, how many workers earn $65 a day? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #537459 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=537459\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the total amount of money earned is 40 * 70 = 2800.\r<BR>\n" );
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document.write( "x = number of workers that earn 65 a day.<BR>\n" );
document.write( "y = number of workers that earn 90 a day.\r<BR>\n" );
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document.write( "65x + 90y = 2800\r<BR>\n" );
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document.write( "x + y = 40\r<BR>\n" );
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document.write( "in the second equation, solve for y to get y = 40 - x\r<BR>\n" );
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document.write( "in the first equation, replace y with 40 - x to get:\r<BR>\n" );
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document.write( "65x + 90(40 - x) = 2800\r<BR>\n" );
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document.write( "simplify to get:\r<BR>\n" );
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document.write( "65x + 3600 - 90x = 2800\r<BR>\n" );
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document.write( "simplify to get:\r<BR>\n" );
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document.write( "-25x + 3600 = 2800\r<BR>\n" );
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document.write( "subtract 3600 from both sides of this equation to get:\r<BR>\n" );
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document.write( "-25x = -800\r<BR>\n" );
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document.write( "divide both sides of this equation by -25 to get:\r<BR>\n" );
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document.write( "x = 32\r<BR>\n" );
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document.write( "in the equation of x + y = 40, replace x with 32 to get:\r<BR>\n" );
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document.write( "32 + y = 40\r<BR>\n" );
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document.write( "solve for y to get y = 8\r<BR>\n" );
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document.write( "you have 32 workers who make 65 a day.<BR>\n" );
document.write( "you have 8 workers who make 90 a day.\r<BR>\n" );
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document.write( "32*65 + 8*90 = 2800\r<BR>\n" );
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document.write( "2800 / 40 = 70\r<BR>\n" );
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document.write( "solution is good.<BR>\n" );
document.write( " </SPAN>\n" );
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