Let the balls meet at time t after the first ball is thrown. Therefore the time for second ball is t-2
height is the same from the ground
Therefore time taken by second ball t-2 = 5-2=3 sec
The first ball reaches the maximum height at t= 40/10 = 4sec
At time t = 4sec, the ball has reached the maximum height and while returning it meet with ball 2, which has travelled for 3 sec
Height travelled by the second ball in 3 sec is the meeting point from the ground and is given by