Calculate the average speed of an automobile that travels 60km east and then 80km north in two hours

We need to calculate speed, so we don't need to consider direction.

speed = distance/time

= (80+60) / 2

=70.

But if we were to calculate velocity, we would need to consider the direction.

The direction of resultant displacement would be in north east direction with displacement

=√60^2 + 80^2

=100km

The average velocity=100/2=50kmph