document.write( "Question 751423: 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?\r
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\n" ); document.write( "The wind speed equals-- \n" ); document.write( "
Algebra.Com's Answer #457387 by ankor@dixie-net.com(22740)\"\" \"About 
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A man flies a small airplane from Fargo to Bismarck, North Dakota --- a
\n" ); document.write( " distance of 180 miles.
\n" ); document.write( "Because he is flying into a head wind, the trip takes him 2 hours.
\n" ); document.write( " On the way back, the wind is still blowing at the same speed, so the
\n" ); document.write( " return trip takes only 1 hour 12 minutes.
\n" ); document.write( " What is his speed in still air, and how fast is the wind blowing?
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\n" ); document.write( "Change 1 hr 12 min: 1 + 12/60 = 1.2 hrs
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\n" ); document.write( "Let s = his speed in still air
\n" ); document.write( "Let w = speed of the wind
\n" ); document.write( "then
\n" ); document.write( "(s-w) = effective speed against the wind
\n" ); document.write( "and
\n" ); document.write( "(s+w) = effective speed with the wind
\n" ); document.write( ":
\n" ); document.write( "Write a distance equation for each way; dist = time * speed
\n" ); document.write( "2(s - w) = 180
\n" ); document.write( "1.2(s+w) = 180
\n" ); document.write( "Simplify both equations, divide the 1st eq by 2, the 2nd eq by 1.2; results:
\n" ); document.write( "s - w = 90
\n" ); document.write( "s + w = 150
\n" ); document.write( "-------------addition eliminates w, find s
\n" ); document.write( "2s = 240
\n" ); document.write( "s = 240/2
\n" ); document.write( "s = 120 mph is the speed in still air
\n" ); document.write( "Find w
\n" ); document.write( "s + w = 150
\n" ); document.write( "120 + w = 150
\n" ); document.write( "w = 150 - 120
\n" ); document.write( "w = 30 mph is the speed of the wind
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\n" ); document.write( "Check in 1st original equation
\n" ); document.write( "2(120-30) = 180
\n" ); document.write( "2(90) = 180 \n" ); document.write( "
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