How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length

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

   =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
200 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec
18

   =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
500
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec.
9

Let the length of the other train be x metres.

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
x + 270 = 500

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
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 =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
72 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec
= 20 m/sec.
18

Time = 26 sec.

Let the length of the train be x metres.

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
x + 250 = 520

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
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 =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
78 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
65
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec.
18 3

Time = 1 minute = 60 seconds.

Let the length of the tunnel be x metres.

Then,
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
800 + x
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
= 65
60 3

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
3(800 + x) = 3900

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
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
=
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
75 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec
18
=
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
125
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
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.

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
Required time =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
500 x 6
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
= 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 =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
2 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec = 5 m/sec.
18 9

4 kmph =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
4 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec = 10 m/sec.
18 9

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

Then,
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
x
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
= 9 and
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
x
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
= 10.

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
9y - 5 = x and 10(9y - 10) = 9x

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
9y - x = 5 and 90y - 9x = 100.

On solving, we get: x = 50.

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
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 =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
4.5 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
m/sec = 5 m/sec = 1.25 m/sec, and
18 4

5.4 km/hr =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
5.4 x 5
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
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

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
8.4x - 10.5 = 8.5x - 12.75

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
0.1x = 2.25

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
x = 22.5

How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
Speed of the train =
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
22.5 x 18
How long does a train 110m long running at the rate of 30 km/hr to cross a bridge 140m in length
km/hr = 81 km/hr.
5


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Exercise :: Problems on Trains - General Questions

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