A train running at 54 kmph takes 20 seconds to pass a platform . Next it takes…
2023
A train running at 54 kmph takes 20 seconds to pass a platform . Next it takes 12 seconds to pass a man walking at 6 kmph in the same direction in which the train is going . Find the length of the train and the length of the platform.
- A.
160m , 120m
- B.
180m , 150m
- C.
240m , 180m
- D.
160m , 140m
Attempted by 3 students.
Show answer & explanation
Correct answer: D
Answer: 160 m , 140 m
Step 1 (find train length): Relative speed when passing the man = 54 km/h - 6 km/h = 48 km/h. Time to pass the man = 12 s = 12/3600 = 1/300 h. Distance covered relative = train length = 48 * (1/300) km = 0.16 km = 160 m.
Step 2 (find platform length): Time to pass the platform = 20 s = 20/3600 = 1/180 h. Total distance covered = (train + platform) = 54 * (1/180) km = 0.3 km = 300 m. Platform length = 300 m - 160 m = 140 m.
Therefore, the train is 160 m long and the platform is 140 m long.