Help, pls

A plane can fly a certain distance in 6 hours with the wind, but can return only three-fourths the distance in the same time. If the speed of the plane in still air is 200 km per hour, find the velocity of the wind.

to the solution, x (the speed of the wind) is 200/7. But to the answer key it is 80 km/h. I am really confused :/

Thanks a lot. I will tell my teacher about this. I spent hours trying to solve this. I feel tricked :)