Answer:
R= V + W;
x-axis projection: Rcos15° = Vcos30° + Wx;
y-axis projection: Rsin15° = Vsin30° + Wy.
From here Wx = 330cos15° - 390cos30° = - 19.0 mi/h
Wy = 330sin15° - 390sin30° = - 109.6 mi/h
So W = ((- 19.0)2 + (- 109.6)2)1/2 = 111.2 mi/h;
tanθ = Wy/Wx = 109.6/19.0; θ = tan-1(109.6/19.0) + 180° = 260.2°