The average speed of a mass point during a given time interval is defined as the ratio of the distance traveled by the masspoint during the time interval and the time elapsed during the time interval.
Definition of average speed in symbols:
vav = s / Δt
In this definition, s denotes the distance traveled and Δt the time elapsed. The definition takes into account varying values of the speed throughout the given time interval of duration Δt.
The SI-unit of average speed is m/s.