Flying against the wind, an alrplane travels 4700 kilometers in 5 hours. Flying with the wind, the same plane travels 9520 kilometers in 7 hours. What is the rate of the plane in still air and what is the rate of the wind?
+37146 4700 / (a-w) = 5 9520 / (a+w) = 7 <===== re-arrange to solve for 'a' : (9520-7w) / 7 = a = 1360 -w
Sub in the red equation for 'a' then solve for 'w' :
4700/ (1360-w - w) = 5
w = 210 km/hr
a = 1360 -210 = 1150 km/hr
