A train passes a platform 90 metre long in 30 seconds and

A train passes a platform 90 metre long in 30 seconds and a man standing on the platform in 15 seconds. The speed of the train is :

Let the length of the train be x
According to the question,

Speed of the train =	x + 90	=	x
	30		15

⇒ x + 90 = 2x
⇒ x = 90 m

∴ Speed of train =	90
	15

= 6 m/s = 6 ×	18	kmph
	5

= 21.6 kmph