The true velocity is 250 km/h.
Explanation:
As the aircraft is moving with speed of 300 km/h and the wind velocity is in east direction with the magnitude of 60 km/h. The resultant velocity or the true velocity can be found by the vector addition of the velocities.
If the true velocity is represented as V and the velocity of aircraft is represented as vₐ and the velocity of wind as vₓ, then
V² = vₐ² + vₓ² - vₐ.vₓ cosθ
So, the angle formed between them is 30°
Then, V² = (300)² + (60)² - 2×(300×60) cos 30°
V²=90000+3600-31177=62423
V =250 km/h
So, the true velocity is having magnitude of 250 km/h.
Thus, the true velocity is 250 km/h.