Question

A 270 metres long train running at the speed of 120 kmph crosses another train running in opposite direction at the speed of 80 kph in 9 seconds. What is the length of the other train

Answer 1

Relative speed = (120 + 80) km/hr
   =200 x(5/18)m/sec
   =500/9    m/sec.

Let the length of the other train be x metres.
Then,(x + 270)/9=500/9

 x + 270 = 500
x = 500 - 270
 x = 230.