Answer:
The stone takes 2.55 sec to reach a maximum height of 31.89 m
Step-by-step explanation:
Vertical Motion
When an object is thrown vertically up with a speed vo, it loses speed because of the effect of the gravity and gains height until the speed is eventually zero. The height attained at that time is called maximum height, and can be calculated as follows:

Since vo=25 m/s

Also, the time taken to reach the maximum height is calculated by:


The stone takes 2.55 sec to reach a maximum height of 31.89 m