Question

DIMENSION OF VELOCITY

Answer 1

velocity = change in displacement / time duration

Length and time are fundamental dimensions. So others are expressed in terms of them.

so  [ Velocity ]  = dimensions of velocity =  [ displacement ] / [ time ]
                        = L / T  or  L T^-1

Answer 2

velocity = displacement / time

Length
 in dimensional formula is given by [L] and time is given by [T]
 so 
[ Velocity ]  =  [ displacement ] / [ time ]
                  $= [L]/[T] \\ = LT^{-1}$