A train 120 meters long passes a man running at 6 km/h in the same direction in 6 seconds. What is the speed of the train?
Show answer & explanation
Correct answer: D
Explanation
Given:
Length of train = 120 m
Time = 6 s
Speed of man = 6 km/h
Formula:
Relative speed = Distance / Time
Relative speed = 120 / 6 = 20 m/s
Speed of man = 6 × 5/18 = 5/3 m/s
Speed of train = 20 + 5/3 = 65/3 m/s
= (65/3) × 18/5 = 78 km/h