50 miles per hour is the rate (speed) of the wind.
Step-by-step explanation:
Let consider the variable ‘x’ for speed of wind.
Below we write two values of the speed of the airplane in the air in terms of ‘x’:
1. Subtract wind speed from airplane speed: 250 - x.
2. Add wind speed to the airplane speed against the wind: 150 + x.
And now, set these above two expressions equal to each other to find x (wind speed),
250 – x = 150 + x
2x = 100
x = 50 miles per hour