What is the initial velocity of an object falling freely (in $m/s$)?

$A$ particle is dropped from the top of a tower. The distance covered by it in the last one second is equal to the distance covered by it in the first three seconds. The height of the tower is $....m$

$A$ ball is thrown vertically upwards from the top of a tower with a velocity $u$. This ball reaches the ground level with a velocity $4u$. The height of the tower is:

$A$ body falls freely from the top of a tower. It covers $36\%$ of the total height in the last second before striking the ground level. The height of the tower is........$m$

$A$ ball is dropped from a tower of height $80 \,m$. The time it takes to cover the last $50 \%$ of its fall is (acceleration due to gravity $= 10 \,ms^{-2}$)

$A$ body is projected vertically upwards at time $t=0$ and it is seen at a height $H$ at times $t_1$ and $t_2$ seconds during its flight. The maximum height attained is ($g$ is acceleration due to gravity).