Answer:
2.55 seconds
Step-by-step explanation:
Given that,
The initial speed of a projectile, u = 21.8 m/s
The angle of projection,

We need to find the time of flight of the projectile. The formula for the time of flight is given by :

Where
g is the acceleration due to gravity

So, the time of flight of the projectile is 2.55 seconds.