A train takes 24 sec to cross a 480 m platform and 36 sec to cover a 900 m platform. what is the length of the train?

Let the length of the train be x meter and its speed be y m/sec
Then, (x + 480 m) / 24 sec = y ....(i)
and , (x + 720 m) / 36 sec = y ....(ii)
From Eqs (i) and (ii)
(x + 480) / 24 = (x + 900) / 36
⇒ 3x + 1440 = 2x + 1800
∴ Length of train, x= 360m