A train, 150m long, passes a pole in 15 seconds and another

A train, 150m long, passes a pole in 15 seconds and another train of the same length travelling in the opposite direction in 12 seconds. The speed of the second train is

Let the speed of the second train be x m/s

Speed of first train =	150	= 10 m/sec
	15

Relative speed of trains
= (x + 10) m/s
Total distance covered
= 150 + 150 = 300 metre

∴ Time taken =	300
	x + 10

⇒	300	= 12
	x + 10

⇒ 12x + 120 = 300
⇒ 12x = 300 – 120 = 180

⇒ x =	180	= 15 m/s
	12

=	15 × 18	or 54 kmph.
	5