A train crosses a platform 100 m long in 60 seconds at a speed of 45 kmph. The time taken by the train to cross an electric pole is

52 sec

Speed = \(\frac{ Distance}{ Time}\)

Let the length of the train be x

45 x \(\frac{ 5}{18 }\) = \(\frac{\text{100 + x}}{ 60}\)

5 x \(\frac{ 5}{2 }\) = \(\frac{\text{100 + x}}{ 60}\)

\(\frac{ 25}{2 }\) = \(\frac{\text{100 + x}}{ 60}\)

60 x 25 = 2(100 + x)

1500 = 200 + 2x

2x = 1300 

x = 650

The length of the train is 650 m

Time = \(\frac{ Distance}{Speed}\)

Time = \(\frac{ 650}{25/2}\)

Time = \(\frac{1300}{25}\)

Time = 52 seconds