Solving Plane Velocity Relative to Ground: Homework Help

[theskyisgreen]

Homework Statement

An airplane has a velocity relative to the air of 189 m/s in a westerly direction. If the wind has a speed relative to the ground of 50 m/s directed to the north, what is the speed of the plane relative to the ground?

Homework Equations

I'm not entirely sure..

The Attempt at a Solution

I figured speed of plane relative to the ground = speed of plane relative to the air + speed of air relative to ground.
So I put in x=189+50
Our homeworks are put online, and I already found out this answer was wrong.

If anyone could help that'd be great! thanks!

 

[Keldon7]

I would just add them vectorially, were the plane's velocity relative to the ground.. I'm not sure what they mean exactly by relative to the air, considering the vectors are perpendicular.