What is the time taken by a train running at 54 km/hr to cross a man standing on a platform. the length of the train being 180 m?

12 seconds

Speed = \(\frac{Distance}{Time }\)

Time = \(\frac{Distance}{Speed }\) 

Speed in m/s = 54 x \(\frac{5 }{18 }\) = 15 m/s

Time = \(\frac{Distance}{Speed }\) 

Time = \(\frac{180}{15}\) 

Time = 12 seconds

*Note* - To convert km/hr to m/s = \(\frac{5 }{ 18}\)

To convert m/s to km/hr = \(\frac{18 }{5 }\)