Q. Two trains cross each other in 20 seconds moving in same direction at speeds 72 km/h and 54 km/h. What is their total length?
✅ Correct Answer: (C)
400 m
Explanation: Relative speed = (72−54)×5/18 = 5 m/s → Length = 5×20 = 100 m (combined concept-based).
Explanation by: Hriday
Relative speed = (72−54)×5/18 = 5 m/s → Length = 5×20 = 100 m (combined concept-based).