Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 8)
8.
A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Answer: Option
Explanation:
| Formula for converting from km/hr to m/s: X km/hr = |  |
X x | 5 |  |
m/s. |
| 18 |
| Therefore, Speed = | |
45 x | 5 | m/sec |
= | 25 | m/sec. |
| 18 | 2 |
Total distance to be covered = (360 + 140) m = 500 m.
| Formula for finding Time = | |
Distance | |
| Speed |
 Required time = |
|
500 x 2 | sec |
= 40 sec. |
| 25 |
Discussion:
78 comments Page 4 of 8.
Praveena said:
10 years ago
Why should we add 360 and 140?
A train of length 360 is moving on 140 m bridge. It is not covering 360 m distance and 140 m distance. Then why should we add two lengths?
A train of length 360 is moving on 140 m bridge. It is not covering 360 m distance and 140 m distance. Then why should we add two lengths?
Chetan said:
10 years ago
Discussion was very nice it's very clear to all.
Syed khamar said:
10 years ago
S = 45*5/18 => 25/2.
Now train passes platform = 360+140/25/2.
= 500*2/25.
= 40 sec.
Now train passes platform = 360+140/25/2.
= 500*2/25.
= 40 sec.
Prasun jana said:
10 years ago
Speed = 45*(5/18) = 12.5.
= (360+140)/12.5 = 40.
= (360+140)/12.5 = 40.
Aditya said:
1 decade ago
From where did 45*(5/18) came please explain?
Saiteja said:
1 decade ago
Train speed = 45 km/hr.
= 45*(5/18) = 12.5 m/sec.
140 m long bridge cross in = 140/12.5 = 11.2 sec.
Including train length crossing time i.e. 360/12.5 = 28.8 sec.
Total = 11.2+28.8 = 40 sec.
= 45*(5/18) = 12.5 m/sec.
140 m long bridge cross in = 140/12.5 = 11.2 sec.
Including train length crossing time i.e. 360/12.5 = 28.8 sec.
Total = 11.2+28.8 = 40 sec.
Joydeep mukherjee said:
1 decade ago
There are no starting and end point mentioned in the question.
Whenever, you get this type of question, just.
Total length = 360+140 m = 500 m.
Whenever, you get this type of question, just.
Total length = 360+140 m = 500 m.
Vishal said:
1 decade ago
Not train is add own length + Pass platform length.
E.g: Train length 345.
Platform 456.
Train length + Platform length.
345+456 = 801.
Now you got it.
E.g: Train length 345.
Platform 456.
Train length + Platform length.
345+456 = 801.
Now you got it.
Ankit Shukla said:
1 decade ago
I think total distance is 360+140+360 = 860 m.
Because the length is started from the starting point to end point of the train.
Because the length is started from the starting point to end point of the train.
Saud said:
1 decade ago
Length Of the train = 360m.
Speed of train = 45km/hr.
Converting it into m/s = 45*1000/3600.
= 45*5/18 (after basic cancellation).
= 25/2 m/s.
Now, let time required by train to cover 140m long bridge = x sec.
Therefore, t = d/s.
x= (train length + platform length) /speed of train.
Therefore, x= (360+140) / 25/2.
x = 500*2/25.
x = 40 sec.
Easiest some until now. Thank You. Hope it helped you.
Speed of train = 45km/hr.
Converting it into m/s = 45*1000/3600.
= 45*5/18 (after basic cancellation).
= 25/2 m/s.
Now, let time required by train to cover 140m long bridge = x sec.
Therefore, t = d/s.
x= (train length + platform length) /speed of train.
Therefore, x= (360+140) / 25/2.
x = 500*2/25.
x = 40 sec.
Easiest some until now. Thank You. Hope it helped you.
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