Question 1103971
Flying with the wind, a small plan flew 300 miles in 2 hours. Against the wind, the plane could fly only 270 miles in the same amount of time. Find the rate of the plane in calm air and the rate of the wind. 
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Find the 2 groundspeeds, upwind and downwind.
The plane's airspeed is the average.
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Windspeed is the difference between airspeed and groundspeed.