Question: A train travels from city X to city Y at a speed of 80 km/h and returns at a speed of 60 km/h. What is the average speed for the entire journey?
Options:
Correct Answer: 72 km/h
Solution:
Average speed = 2xy / (x + y) where x = 80 and y = 60. Average speed = 2 * 80 * 60 / (80 + 60) = 72 km/h.