Step-by-step explanation:
Speed is the rate of change of distance with time. It is a scalar quantity with magnitude both no direction. 
 Speed = 
 
 
The unit is m/s or km/hr or mile/hr
Distance covered is simply the length of the path traveled. 
 The unit is m or km or miles 
Time taken is the duration of an event. 
 The unit is seconds or minutes or hour.