Question

how shhould find velocity of a bulet

Answer 1

Find the time taken by bullet to cover 200 m 

and use this formula velocity(v) = displacement/time(t)
                                      v = 200/t

Answer 2

You can use the formulas given below to find the velocity of a bullet :
- velocity = displacement traveled by the bullet / given time
- v = m+M/m.√(2gh)   [in case of a bullet embedded with in a block]
- v = √(2gh)   [in case of a bullet emerges out of a block]