Answer: both balls will go the same height.
Step-by-step explanation:
The height is related only with the vertical velocity.
With the angle of 30° respect the horizontal you can calculate the vertical velocity from the sine ratio:
sin(30°) = vertical speed / speed = > vertical speed = speed * sin(30°)
=> vertical speed = speed * 0.5 = (2v) * 0.5 = v.
That means that both balls are thrown with the same vertical velocity, therefore both balls will go the same height.