From a tower of height H, a particle is thrown vertically upwards with a speed of u. The time taken by the particle, to hit the ground is n times that taken by it to reach the highest point of its path.
The relation between H, u and n are:
2 g H = n2u2
g H = (n - 2)2 u2
2 g H = nu2 (n - 2)
g H = (n - 2)u2