Subject: General Aptitude · Chapter: Problems on Trains · Exam: · Marks: · Difficulty:
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.
Answer
Answer (as printed):
Explanation
Let the length of train be x metres and the length of platform be y metres. Speed of the train relative to man = (54 – 6) kmph = 48 kmph 5 40 = 48 × m/sec = m/sec . 18 3 In passing a man, the train covers its own length with relative speed. 40 ∴ Length of train = (Relative speed × Time) = × 12 m = 160 m. 3 5 Also, speed of the train = 54 × m/sec = 15 m/sec. 18 x+y ∴ = 20 ⇔ x + y = 300 ⇔ y = (300 – 160) m = 140 m. 15 PROBLEMS ON TRAINS 615
Explanation as extracted from the printed page; notation may be imperfect.