A train passes a running man — Aptitude Question
A train passes a running man: A train 150 m long running at 68 km/h passes a man running at 8 km/h in the same… Answer and worked solution on CodeKairo.
- Topic: Time, Speed & Distance
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
A train 150 m long running at 68 km/h passes a man running at 8 km/h in the same direction. How long does it take?
Options
- 7 s
- 8 s
- 9 s
- 10 s
Show the answer and the worked solution
Correct answer: C. 9 s
Worked solution
- Relative speed = 60 km/h = 60 × 5/18 = 50/3 m/s.
- Time = 150 ÷ (50/3) = 150 × 3/50 = 9 s.
Answer: 9 s.
The idea
A person contributes no length. Use the relative speed and the train's length alone.
Shortcut. At a relative 60 km/h the train gains 1 km a minute, so 150 m takes 0.15 min = 9 s.
Common trap. 8 s — ignoring the man's speed and using 68 km/h alone (≈ 18.9 m/s), which gives about 7.9 s; the relative speed is 60 km/h.