document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1193697>Question 1193697</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 head wind, 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? </SPAN>\n" );
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document.write( "His speed flying against the wind is 180/2 = 90mph.<br><BR>\n" );
document.write( "1 hour 12 minutes is 1 1/5 hours, or 6/5 hours. His speed flying with the wind is 180/(6/5) = 150 mph.<br><BR>\n" );
document.write( "So<br><BR>\n" );
document.write( "plane speed plus wind speed = 150mph<BR>\n" );
document.write( "plane speed minus wind speed = 90mph<br><BR>\n" );
document.write( "You can solve that algebraically if you want (or if you need to)...<br><BR>\n" );
document.write( "p+w=150<BR>\n" );
document.write( "p-w=90<BR>\n" );
document.write( "solve using basic algebra<br><BR>\n" );
document.write( "But this kind of problem can be solved using logical reasoning.<br><BR>\n" );
document.write( "Adding the wind speed to the plane's speed gives 150mph; subtracting it from the plane's speed gives 90mph.  That means the plane's speed is halfway between 90 and 150mph -- 120mph.  And then the wind speed is the difference between 120mph and 150mph (or between 120mph and 90mph) -- 30mph.<br><BR>\n" );
document.write( "ANSWERS:<BR>\n" );
document.write( "plane speed: 120mph<BR>\n" );
document.write( "wind speed: 30mph<br><BR>\n" );
document.write( " </SPAN>\n" );
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