A train crosses a pole — Aptitude Question
A train crosses a pole: A train 180 m long crosses a pole in 12 seconds. What is its speed? Answer and worked solution on CodeKairo.
- Topic: Time, Speed & Distance
- Section: Quantitative Aptitude
- Difficulty: Easy
- Time target: 45 seconds
Question
A train 180 m long crosses a pole in 12 seconds. What is its speed?
Options
- 48 km/h
- 54 km/h
- 60 km/h
- 72 km/h
Show the answer and the worked solution
Correct answer: B. 54 km/h
Worked solution
- Distance = 180 m in 12 s → 15 m/s.
- 15 × 18/5 = 54 km/h.
Answer: 54 km/h.
The idea
A pole, a person or a signal post has no length, so the train covers only itself. A platform or bridge adds its own length.
Shortcut. 180 m in 12 s is 15 m/s, and since 5 m/s = 18 km/h, 15 m/s = 3 × 18 = 54 km/h.
Common trap. 60 km/h — rounding the conversion factor 3.6 up to 4 (15 × 4); 15 × 18/5 is exactly 54 km/h.