Aplane flies at x miles per hour in still air. flying with a tailwind, its speed is 485 mi/hr. against the wind, it's air speed is only 445 mi/hr. what is the speed of the wind

20mi/hr
When an object flying with a tailwind, the speed of wind will increase the object velocity. When an object flying against the wind, the speed of wind will decrease the object velocity. Let say the speed of the wind is v. Then, the equation would be:
x + v= 485mi/hr
x - v =445mi/hr
-
x+ v - (x-v) = 485-445
2v= 40
v=20