Two trains of equal length are running on parallel tracks in the same direction at 191 km/h


Correct Answer:

Description for Correct answer:

Let the length of each train = l Relative speed=\( \Large \left(46-36\right) \times \frac{5}{18}=\frac{25}{9} \) m/sAccording to the question, \( \Large \frac{l+l}{\frac{25}{9}}=36 \)=2l=\( \Large \frac{25}{9} \times 36 =l=50m \)

\( \Large \therefore \)length of each train = 50m


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Exercise :: Problems on Trains - General Questions

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7. 

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:

A. 50 m
B. 72 m
C. 80 m
D. 82 m

Answer: Option A

Explanation:

Let the length of each train be x metres.

Then, distance covered = 2x metres.

Relative speed = (46 - 36) km/hr

   =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
10 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec
18

   =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
25
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec
9

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
2x = 25
36 9

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
2x = 100

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x = 50.

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Exercise :: Problems on Trains - General Questions

11. 

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
E. None of these

Answer: Option A

Explanation:

Relative speed = (120 + 80) km/hr

   =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
200 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec
18

   =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
500
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec.
9

Let the length of the other train be x metres.

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x + 270 = 500

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x = 230.

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12. 

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: Option D

Explanation:

Speed =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
72 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec
= 20 m/sec.
18

Time = 26 sec.

Let the length of the train be x metres.

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x + 250 = 520

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x = 270.

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Exercise :: Problems on Trains - General Questions

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17. 

A train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:

Answer: Option C

Explanation:

Speed =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
78 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
65
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec.
18 3

Time = 1 minute = 60 seconds.

Let the length of the tunnel be x metres.

Then,
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
800 + x
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
= 65
60 3

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
3(800 + x) = 3900

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x = 500.

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Exercise :: Problems on Trains - General Questions

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22. 

Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.

A. 12 sec
B. 24 sec
C. 48 sec
D. 60 sec

Answer: Option B

Explanation:

Relative speed = = (45 + 30) km/hr
=
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
75 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec
18
=
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
125
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec.
6

We have to find the time taken by the slower train to pass the DRIVER of the faster train and not the complete train.

So, distance covered = Length of the slower train.

Therefore, Distance covered = 500 m.

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
Required time =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
500 x 6
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
= 24 sec.
125

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Exercise :: Problems on Trains - General Questions

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27. 

A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. The length of the train is:

A. 45 m
B. 50 m
C. 54 m
D. 72 m

Answer: Option B

Explanation:

2 kmph =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
2 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec = 5 m/sec.
18 9

4 kmph =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
4 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec = 10 m/sec.
18 9

Let the length of the train be x metres and its speed by y m/sec.

Then,
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
= 9 and
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
= 10.

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
9y - 5 = x and 10(9y - 10) = 9x

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
9y - x = 5 and 90y - 9x = 100.

On solving, we get: x = 50.

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
Length of the train is 50 m.

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28. 

A train overtakes two persons walking along a railway track. The first one walks at 4.5 km/hr. The other one walks at 5.4 km/hr. The train needs 8.4 and 8.5 seconds respectively to overtake them. What is the speed of the train if both the persons are walking in the same direction as the train?

A. 66 km/hr
B. 72 km/hr
C. 78 km/hr
D. 81 km/hr

Answer: Option D

Explanation:

4.5 km/hr =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
4.5 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec = 5 m/sec = 1.25 m/sec, and
18 4

5.4 km/hr =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
5.4 x 5
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
m/sec = 3 m/sec = 1.5 m/sec.
18 2

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

Then, (x - 1.25) x 8.4 = (x - 1.5) x 8.5

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
8.4x - 10.5 = 8.5x - 12.75

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
0.1x = 2.25

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
x = 22.5

Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
Speed of the train =
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
22.5 x 18
Two trains of equal length are running on parallel tracks in the same direction at 191 km/h
km/hr = 81 km/hr.
5


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