2012 · Q7
A 60 m long train travels at a uniform speed of 72 km/hour. It passes non-stop along the 600 m platform of a wayside station. What is the elapsed time for the train to entirely clear the platform ?
General Mental Ability, Quantitative Aptitude and StatisticsTime, work and measurement
- A30 seconds
- B31 seconds
- C32 seconds
- D33 seconds
Explanation
To entirely clear the platform, the train must travel the platform length plus its own length: 600 + 60 = 660 m. The speed 72 km/h converts to 72 × 1000/3600 = 20 m/s. Time = distance/speed = 660/20 = 33 seconds. Using only the 600 m platform (option A, 30 s) is the classic distractor — it forgets the train's own length.