A train passes a pole — Aptitude Question
A train passes a pole: A 150 m long train passes a pole in 15 seconds. What is its speed in km/h? Answer and worked solution on CodeKairo.
- Topic: Time, Speed & Distance
- Section: Quantitative Aptitude
- Difficulty: Easy
- Time target: 40 seconds
Question
A 150 m long train passes a pole in 15 seconds. What is its speed in km/h?
Options
- 30 km/h
- 36 km/h
- 40 km/h
- 45 km/h
Show the answer and the worked solution
Correct answer: B. 36 km/h
Worked solution
- Distance = train length = 150 m; time = 15 s; speed = 10 m/s.
- 10 m/s × 18/5 = 36 km/h.
Answer: 36 km/h.
The idea
m/s to km/h: multiply by 18/5; the reverse: multiply by 5/18. A train passing a point covers its own length; passing a platform, its length plus the platform's.
Shortcut. 10 m/s = 36 km/h is the anchor pair; 150 m in 15 s is exactly 10 m/s, so 36 km/h with no arithmetic.
Common trap. 40 km/h — rounding the factor 3.6 up to 4 (10 × 4); 10 × 18/5 is exactly 36 km/h.