A train of length 540 m crosses a bridge of length 390 m in 30 seconds.  What is the speed of the train (in km/h)?

120 119 111.6 125

111.6

Distance = Speed × Time (540 + 390) = S × 30 ⇒ S = \(\frac{930}{30}\) = 31 m/sec To convert km/h into m/sec .   X m/sec  ×   \(\frac{18}{5}\) = Y km/h 31 m/sec × \(\frac{18}{5}\) = 111.6 km/h