Answer: 16 kph
Explanation:
Average Speed = Total Distance/ Total Time
Distance = Speed x Time
The Distance between A and B is 20 kph
Time(A-B) = 1.5 hrs
Time(B-A) = 1 hour
Total Time = 2.5 hrs
Total Distance = 20 + 20 = 40 km
Average Speed = 40 km / 2.5 hrs = 16 kmph