A train crosses a platform 180 m long in 60 sec at a speed of 72 km/h. The time taken by the train to cross an electric pole is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e 51 sec
| Understanding | Application |
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Speed = Distance / time To convert speed from km/h to m/s ⇒ Speed(km/h) × (5 / 18) = speed(m/s) |
First, we will convert speed into m/s ⇒ 72 × (5 / 18) ⇒ 20m/s Let the speed of the train be 'T'm so the distance covered by the train while covering the platform ⇒ T + 180 By the speed-distance formula ⇒ 20 = (T + 180) / 60 ⇒ 1200 = T + 180 ⇒ T = 1020 m For covering the pole train has to cover a distance equal to the length of the train. ⇒ 20 = 1020 / t ⇒ t = 51 Sec |