Velocity is defined as speed in a specified direction. The formula for calculating speed is expressed as
Speed = distance/time
Since the direction is north, time = 20 minutes and distance = 1.6km
We can convert 20 minutes to hour(60 minutes = 1 hour). it becomes 20/60 = 1/3 hour
Speed = 1.6/(1/3) = 4.8 km/hr
The average velocity is 4.8km/hr northwards