Two trains move in the same direction at 50 kmph and 32 kmph respectively . A…
2024
Two trains move in the same direction at 50 kmph and 32 kmph respectively . A man in the slower train observes the 30 seconds elapse before the faster train completely passes by him. What is the length of faster train ?
- A.
150 m
- B.
90 m
- C.
120 m
- D.
100 m
Attempted by 6 students.
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Correct answer: A
Answer: 150 m
Key idea: Use relative speed between the trains; the faster train covers its own length relative to the man in the slower train.
Compute relative speed: 50 − 32 = 18 km/h = 18 × (5/18) = 5 m/s.
Distance covered in 30 s: 5 m/s × 30 s = 150 m.
Alternative using km/h: Length in km = 18 × (30/3600) = 3/20 km = 0.15 km = 150 m.
Therefore the length of the faster train is 150 m.