document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=316321>Question 316321</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An airplane takes 6 hours to travel a distance of 3960 km against the wind. The return trip takes 5 hours with the wind. What is the rate of the plane in still air and what is the rate of the wind?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #226275 by </B><A HREF=/tutors/aboutme.mpl?userid=nyc_function><B>nyc_function(2741)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nyc_function><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=nyc_function><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=226275\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I can see that we have a system of linear equations in two variables hidden in this travel application.\r<BR>\n" );
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document.write( "Let p = speed of plane\r<BR>\n" );
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document.write( "Let w = speed of wind\r<BR>\n" );
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document.write( "Objects traveling against the wind tend to slow down a bit and object traveling with the wind move faster.  Agree?  Try it on your bike on a windy day.\r<BR>\n" );
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document.write( "Against the wind:\r<BR>\n" );
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document.write( "time = 6 hours\r<BR>\n" );
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document.write( "speed = p - w\r<BR>\n" );
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document.write( "distance = 3960 km\r<BR>\n" );
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document.write( "================\r<BR>\n" );
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document.write( "With the wind:\r<BR>\n" );
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document.write( "time = 5 hours\r<BR>\n" );
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document.write( "speed = p + w\r<BR>\n" );
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document.write( "distance = 3960 km\r<BR>\n" );
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document.write( "================\r<BR>\n" );
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document.write( "From the tables above, we make the following equations:\r<BR>\n" );
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document.write( "6(p - w) = 3960<BR>\n" );
document.write( "5(p + w) = 3960\r<BR>\n" );
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document.write( "6p - 6w = 3960...Equation A<BR>\n" );
document.write( "5p + 5w = 3960...Equation B\r<BR>\n" );
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document.write( "Can you take it from here?\r<BR>\n" );
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document.write( "TIP: Use the substitution method to find p and w.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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