A car travels 150 km at 30 km/h and returns at 50 km/h. What is the average speed?

A. 37.5 km/h
B. 38 km/h
C. 40 km/h
D. 42 km/h

Solution:
Average Speed = (2xy) ÷ (x + y) = (2×30×50) ÷ (30+50) = 3000 ÷ 80 = 37.5
Answer: A