If a train 110 m long passes a telegraph pole in 3 seconds, then the time taken by it to cross a railway platform 165 m long, is

7.5 sec

Speed of train = \(\frac{ Distance}{ Time}\)

Speed of train = \(\frac{ 110}{ 3}\) 

Now, the time taken by the train to cross a railway platform:

Time = \(\frac{ Distance}{Speed }\)

Time = \(\frac{ \text{110 + 165}}{\text{110/3} }\)

Time = \(\frac{\text{275 Χ 3}}{110 }\)

Time = 7.5 sec