document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1120070>Question 1120070</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A man flies a small airplane from Fargo to Bismarck, North Dakota a distance of 180 miles. Because he is flying into a headwind, the trip takes him 2 hours. On the way back, the wind is still blowing at the same speed, so the return trip takes only 1 hour 12 minutes. What is his speed in still air, and how fast is the wind blowing?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #735739 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=735739\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "The solution can be obtained informally on a path nearly identical to the formal algebraic solution provided by the other tutor.<br><BR>\n" );
document.write( "The average speed against the wind is 180 miles / 2 hours = 90mph.  The average speed with the wind is 180 miles / 1.2 hours = 150mph.<br><BR>\n" );
document.write( "One speed is the speed of the airplane plus the speed of the wind; the other is the speed of the airplane minus the speed of the wind.<br><BR>\n" );
document.write( "That is a kind of situation that shows up in many different kinds of problems.  Logical analysis says that the speed of the airplane is halfway between the two average speeds; then the wind speed is the difference between the plane's speed and average speed on either of the legs.<br><BR>\n" );
document.write( "Halfway between 90 and 150 is 120.  The speed of the airplane is 120mph; the speed of the wind is 150-120 = 120-90 = 30mph. </SPAN>\n" );
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