Average speed is distance travelled divided by time taken. Velocity describes speed in a stated direction; average velocity uses displacement divided by time. Use compatible units and distinguish average speed over a journey from instantaneous speed at a particular moment. Example: An object travels 105 m in 9 s. Calculate average speed. v = s/t = 105/9 = 11.667 m/s. Rearrange the relationship before substituting if a different quantity is required. Use clear labels. Give a reason. Use evidence.