An airplane travels 2004 km against the wind in 3 hours.
Thus, speed = 2004/3 = 668 km/hr ,
and
An airplane travels 2544 km against the wind in 3 hours.
Thus, speed = 2544/3 = 848 km/hr
The speed of the plane in still air = (848 + 668 )/2
= 758 km/hr
Thus, the speed of wind is 848 - 758 = 90 km/hr