A train running at 54 km/h crosses a 400 m long platform in 36 seconds. How long is the train?

Explanation

1. 01

   54 km/$h = 15$ m/s.

2. 02

   Distance covered while crossing $= 15 \times 36 = 540$ m.

3. 03

   This is train + platform, so the train is $540 - 400 = 140$ m.