UPSC CDS Math Height and Distances Questions

Let the plane be at point A making an angle θ with point P at t seconds. In (t + 30) seconds, plane reaches plane B, where it makes an angle θ with point P.
In 3 minutes, i.e., in 180 seconds, the plane covers 360°. Let it make an angle of y° in 30 seconds. Then:

y

30

=

360

180

⇒y=60°
Now, to cover a distance from point A to point P, plane must make an angle of (60 + 150), i.e., 210°. Now, if the plane makes an angle of 60° from the centre in 30 seconds, then in x seconds, it has to make an angle of 210°.
Now,

210

x

=

60

30

=x=105°