Question 82373
Given an equation in terms of Height and time

NOw the first part says how high after 3secs.
So you are given time and you have to find H. In the given equation, substitute 3 in place of T and you'll get the height
Similarly when it says how much time to reach 169m, you are given Height and you have to find T. SO replace H with 169 and solve for T

For the ball to hit the ground, H = 0 so replace H with 0 and solve for T

Please try now.