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Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is ?

  • 1:3
  • 3:2
  • 3:5
  • 3:7

Answer: Option B

Explanation:

Let the speeds of the two trains be x m/sec and y m/sec respectively.

Then, length of the first train = 27x metres,
Length of the second train = 17y metres.
[because distance = speed*time]

27x+17yx+y=23=>27x+17y=23x+23y=>4x=6y=>xy=64


So ratio of the speeds of train is 3:2

Similar Questions :

1. Speed of a goods train is 72 km/hr. This train crosses a 250 meter platform in 26 seconds. Then find the length of goods train.

  • 250 meters
  • 260 meters
  • 270 meters
  • 280 meters

Answer: Option C

Explanation:

First convert speed from km/hr to m/sec

So, Speed = 72*(5/18) = 20 m/sec
Time = 26 seconds

Let the length of the train be x meters.
We know, Distance = Speed*Time.
[you can remember this formula as remembering DUST = D*ST... Distance=Speed*Time]

x+250 = 20*26
=> x = 270 meters

So length of the goods train is 270 meter

2. Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is ?

  • 40 meter
  • 45 meter
  • 50 meter
  • 55 meter

Answer: Option C

Explanation:

Let the length of each train is x meter
Distance will be x+x = 2x

Relative Speed = 46-36 = 10 km/hr
= 10*(5/18) = 25/9 m/sec

Distance = Speed*Time

2x=259∗362x=100=>x=50


So length of both the trains are 50 meters

3. How long does a train 110 meters long running at the speed of 72 km/hour take to cross a bridge 132 meters in length ?

  • 15 seconds
  • 12.1 seconds
  • 10 seconds
  • 8.1 seconds

Answer: Option B

Explanation:

Speed = 72 km/hour = 72*(5/18) m/sec
= 20 m/sec

Total distance to be covered = 110+132 = 142 meters

Time = Distance/Speed
= 242/20 = 12.1 seconds

4. A train is 360 meter long is running at a speed of 45 km/hour. In what time will it pass a bridge of 140 meter length.

  • 20 seconds
  • 30 seconds
  • 40 seconds
  • 50 seconds

Answer: Option C

Explanation:

Speed = 45 Km/hr = 45*(5/18) m/sec
= 25/2 m/sec
Total distance = 360+140 = 500 meter

Time = Distance/speed
=500∗225=40seconds

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

  • 30 seconds
  • 32 seconds
  • 34 seconds
  • 36 seconds

Answer: Option D

Explanation:

Speed of train relative to jogger = (45-9) = 36 kmph
= 36*(5/18) = 10 m/sec

Distance to cover = 240 + 120 = 360 metres

Time = Distance/Speed
So,
Time=36010=36 Seconds

Read more from - Problems on Trains Questions Answers
Post a comment

  • Goutham 11 years ago

    this can be done as
    relative time=23

    23-27=4(relative time minus the time to cross a pole)
    23-17=6

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