1)Two particles A and B start from the same point on the circumference
of a circle. They travel in opposite directions. They start with
velocity of 3 rev/s and 7 rev/s respectively. They change their
velocities by the same factor of after every time they meet. The speeds
are constant except when
they meet and speeds change instantly.

What is the average speed of the slower particle from the start to the time they meet for the 8th time?
( )7 rev/s
( )0.7 rev/s
( )0.07 rev/s
( )0.007 rev/s

2)Two Jet aircrafts are flying in a straight line horizontally on
different altitudes such that the vertical distance between their
altitudes is 100 km and the pilot of the upper aircraft observes the
lower aircraft at an angle of depression of 30o. After half an hour, the
angle of depression becomes 60o.

Find the distance between the aircrafts after half an hour from the initial point of reference.
Plz provide simple explanation as how u got it

2. It's simply two 30-60-90 triangles. Initially the side opposite to 30 degree is 100 km that means the hypotenuse i.e. distance between the air-crafts is 2*100 = 200 km initially. After half an hour, the side opposite to 60 degree is 100 km that means the hypotenuse i.e. distance between the air-crafts will be 200/3^{0.5} ~ 115.47 km.