Question 585440
With the wind, a jet can fly 1500 mi in 2 hr 30 min.  Against the wind it can fly only 1200 mi in the same time.  find the rate of the jet in still 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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The windspeed is the difference between groundspeed and airspeed.