The speed of a 90 meter long train is 45 km/h. A man is standing right next to the railway line. How much time will the train take to cross the speed increases by 20%?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 6.0 second
Raising 45 km/h by 20% gives 54 km/h, and converting, 54 × 5/18 = 15 m/s.
To pass a man standing still the train has only to cover its own length, 90 m. The time taken is 90 ÷ 15 = 6 seconds.