document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=673180>Question 673180</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An airline carries 180 passengers and 10 tonnes of freight and earns $75000 for its owners in fares and freight charges. On the return trip it carries 100 passengers and 20 tonnes of freight, earning $85000. What is the passenger fare per person and the freight charges per tonne.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #418507 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=418507\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">     An airline carries 180 passengers and 10 tonnes of freight and earns $75000 for its owners in fares and freight charges. On the return trip it carries 100 passengers and 20 tonnes of freight, earning $85000. What is the passenger fare per person and the freight charges per tonne. <BR>\n" );
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document.write( "Let x = cost ($) per person<BR>\n" );
document.write( "and y = cost ($) per ton<BR>\n" );
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document.write( "from:\"180 passengers and 10 tonnes of freight and earns $75000\"<BR>\n" );
document.write( "180x + 10y = 75000<BR>\n" );
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document.write( "from:\"100 passengers and 20 tonnes of freight, earning $85000\"<BR>\n" );
document.write( "100x + 20y = 85000<BR>\n" );
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document.write( "Our simultaneous equations:<BR>\n" );
document.write( "180x + 10y = 75000<BR>\n" );
document.write( "100x + 20y = 85000<BR>\n" );
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document.write( "multiply top equation by -2 and combine with second:<BR>\n" );
document.write( "-360x - 20y = -150000<BR>\n" );
document.write( " 100x + 20y =  85000<BR>\n" );
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document.write( "-260x       = -65000<BR>\n" );
document.write( "x       = -65000/(-260)<BR>\n" );
document.write( "x = $250 (passenger fare per person)<BR>\n" );
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document.write( "freight charges per tonne:<BR>\n" );
document.write( "plug above into:<BR>\n" );
document.write( "100x + 20y = 85000<BR>\n" );
document.write( "100(250) + 20y = 85000<BR>\n" );
document.write( "25000 + 20y = 85000<BR>\n" );
document.write( "20y = 60000<BR>\n" );
document.write( "y = $3000 (per tonne)\r<BR>\n" );
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document.write( " </SPAN>\n" );
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