an airplane flying into a headwind travels 3000 miles in 6 h

an airplane flying into a headwind travels 3000 miles in 6 hours and 15 minutes. on the return flight, the same distance is traveled in 5 hours. find the speed of the airplane in still air.

Solution

d=rt
r=d/t
r=3,000/6.25=480 mph. against the wind.
r=3000/5=600 mph. with the wind.
(600-480)2=120/2=60 mph is the speed of the wind.
Proof:
600-60=540 mph for the plane in still air.
480+60=540 ditto.