Let x be the speed of the plane and y be the speed of wind in mph. While travelling against wind, effective speed is (x-y) mph Time taken to travel 350 miles is 1 hour 10 min = 7/6 hours So----> eqn 1 While travelling with the wind, effective speed is (x+y) mph Time taken to travel 350 miles is 1 hour So -----> eqn 2 Adding (1) and (2) since x + y = 350, y = 350 - 325 = 25 So speed of plane = mph Wind speed = mph :)