Problems On Trains

Two trains, each 100 m long, moving in opposite directions, cross each other in 8 seconds. If one is moving twice as fast the other, then the speed of the faster train is:

A:

30 km/hr

B:

45 km/hr

C:

60 km/hr

D:

75 km/hr

Answer: C

Let the speed of the slower train be x m/sec.

Then, speed of the faster train = 2x m/sec.

Relative speed = (x + 2x) m/sec = 3x m/sec.

	(100 + 100)	= 3x
	8

24x = 200

x =	25	.
	3

So, speed of the faster train =	50	m/sec
	3

=		50	x	18	km/hr
		3		5

= 60 km/hr.

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A goods train runs at the speed of 72 kmph and crosses a 250 m long platform in 26 seconds. What is the length of the goods train?

A:

230 m

B:

240 m

C:

260 m

D:

270 m

Answer: D

Speed =		72 x	5	m/sec	= 20 m/sec.
			18

Time = 26 sec.

Let the length of the train be x metres.

Then,	x + 250	= 20
	26

x + 250 = 520

x = 270.

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

A:

230 m

B:

240 m

C:

260 m

D:

320 m

Answer: A

Relative speed = (120 + 80) km/hr

=		200 x	5	m/sec
			18

=		500	m/sec.
		9

Let the length of the other train be x metres.

Then,	x + 270	=	500
	9		9

x + 270 = 500

x = 230.

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A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger?

A:

3.6 sec

B:

18 sec

C:

36 sec

D:

72 sec

Answer: C

Speed of train relative to jogger = (45 - 9) km/hr = 36 km/hr.

=		36 x	5	m/sec
			18

= 10 m/sec.

Distance to be covered = (240 + 120) m = 360 m.

Time taken =		360	sec	= 36 sec.
		10

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Two trains are moving in opposite directions @ 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is:

A:

36

B:

45

C:

48

D:

49

Answer: C

Relative speed = (60+ 90) km/hr

=		150 x	5	m/sec
			18

=		125	m/sec.
		3

Distance covered = (1.10 + 0.9) km = 2 km = 2000 m.

Required time =		2000 x	3	sec = 48 sec.
			125

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Questions for: Problems On Trains