Find the length of the bridge which a train 130 m long travelling at 45 kmph can cross in 30 seconds, is :

245 m

Speed = \(\frac{ Distance}{ Time}\)

Let the length of the bridge be x

45 x \(\frac{5 }{ 18}\) = \(\frac{ \text{130 + Length of the bridge}}{ 30}\)

\(\frac{25 }{ 2}\) = \(\frac{ \text{130 + x}}{ 30}\)

2(130 + x) = 30 x 25

260 + 2x = 750

2x = 490

x = 245 m