Question 271988
Let the speed of the airplane = x
Let the speed of the wind = y
The airplane travels 600 miles against the wind in 4 hours
   600 = 4*(x-y)  ...(1)
It makes the return trip with the same wind in 2 hours
   600 = 2*(x+y)  ...(2)
(2)*2=>
   1200=4*(x+y)   ...(3)
(2)-(3)=>
 -600 = - 8y
8y=600
y=600/8
y=75 m/h
So, the speed of the wind = y = 75mph