Answer:
10 km, 6.67 km/h
Step-by-step explanation:
The minimum distance between two points is called displacement. It is a vector quantity.
The average velocity is defined as the ratio of total displacement covered to the total time taken. It is also a vector quantity.
Total displacement = 30 - 20 = 10 km south
Total time = 1.5 hour
Average velocity = total displacement / total time
Average velocity = 10 / 1.5 = 6.67 km/h