document.write( "Question 974123: A plane can travel 470mph with the wind and 390mph against the wind. What is the speed of the plane if the air is still? \n" ); document.write( "
Algebra.Com's Answer #596149 by Alan3354(69443)\"\" \"About 
You can put this solution on YOUR website!
It's the average of the 2 groundspeeds, and it's called airspeed.
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