Let
u = initial velocity,
v = final velocity,
s = displacement, and
t = time.
[tex]\text{Average velocity } = \frac{u+v}{2}[/tex]
The equation that links [tex] \frac{u+v}{2} [/tex], s and t is one of the five equations of motion that apply for a constant acceleration:
[tex]s = \frac{u+v}{2}t [/tex]