what air speed and heading would enable a plane to travel [NE] with a ground speed of 275 km/h if there is a wind blowing at 55 km/h from the south?

Vp+Vw = 275km[45o]

Vp + 55km[90o] = 275[45o]
Vp + 55i = 275*cos45 + i275sin45
Vp + 55i = 194.45 + 194.45i
Vp = 194.45 + 194.45i - 55i
Vp = 194.45 + 139.45i = 239.3km[35.6o] =
Velocity and heading of plane.

Check:
194.45+139.45i + 55i =
194.45 + 194.45i = 275[45o]