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:

51 sec 0.51 min 5.1 sec 5.1 min

51 sec

Let length of train = a meter Speed = 72 km/h = 20 m/sec Time = 60 sec Distance = Speed × Time = 20 × 60 = 1200 m According to question a + 180 = 1200 a = 1020 Now , Time to cross pole Time = \(\frac{Distance}{Speed}\)  = \(\frac{1020}{20}\) = 51 sec