A train passes a 50 metres long platform in 14 seconds and a man standing on the platform in 10 seconds. The speed of the train is:

Answer: (d)

Let the length of train be L m.

\(\frac{L}{10} = \frac{L + 50}{14}\)

14L = 10L + 500

L = 125 m.

\(Speed = \left ( \frac{25}{2} \right )\) m/s

= \(\left ( \frac{25}{2} \right ) \times  \frac{18}{5}\)

= 45 km/hr