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 6 of 8.
Anonymous said:
9 years ago
In this question, the length of the bridge is shorter than that of the train. Then why we go for adding the two lengths?
Sujith kumar said:
9 years ago
Speed = 45km/hr = 45 * 1000/60 * 60 = 12.5m/ec.
Length = Speed * Time.
360 + 140 = 12.5 * time.
Time = 500/12.5 = 40sec.
Length = Speed * Time.
360 + 140 = 12.5 * time.
Time = 500/12.5 = 40sec.
(1)
Shruthi Bhosle said:
9 years ago
We should find time only for distance of 140m long, why we add (360 + 140).
Uzair said:
9 years ago
What about this?
What is the speed of a 140 m long train cross a 1 km bridge in 12 sec?
What is the speed of a 140 m long train cross a 1 km bridge in 12 sec?
Aishwarya said:
9 years ago
What about this?
Let time be x sec.
Length of the train = 360/x,
Length of the bridge = 140m,
Required time = (360+140)/x,
Which is , x = 500m,
Speed= (45 * 5/18) = 25/2 m/sec,
Time = distance/ time,
500 * 25/2 = 40sec.
Is this method right?
Let time be x sec.
Length of the train = 360/x,
Length of the bridge = 140m,
Required time = (360+140)/x,
Which is , x = 500m,
Speed= (45 * 5/18) = 25/2 m/sec,
Time = distance/ time,
500 * 25/2 = 40sec.
Is this method right?
Jyoti said:
9 years ago
Train takes 25/2 sec to travel 360 m, then how it's possible that it is taking same 25/2 sec to travel 500 m as well if it takes 25/2 sec for 360 m then it should take x sec to travel 500 m and then cross multiply and get value of x and that will be time taken to travel 500 m.
Am I right? Please explain.
Am I right? Please explain.
Hardik Patel said:
9 years ago
@Shruthi.
140m is a only bridge length.
If you consider only 140 m length it means only first point of train cross a bridge not whole train.
If you add a 340 m(length of the train) in 140m it means the whole train cross the bridge.
so add (360+140).
140m is a only bridge length.
If you consider only 140 m length it means only first point of train cross a bridge not whole train.
If you add a 340 m(length of the train) in 140m it means the whole train cross the bridge.
so add (360+140).
Sameena kabir said:
7 years ago
Please, anyone can solve this one I can't understand how to tackle this one?
A train travell 34 km in 54mints. How far a train travell in 60 mints.
A train travell 34 km in 54mints. How far a train travell in 60 mints.
Sarang said:
7 years ago
Distance = speed *time.
360+140=45*5/18*time,
500=5*5*/2*time,
500=25/2*time,
500=12.5*time,
500/12.5=time,
Time = 40 second.
360+140=45*5/18*time,
500=5*5*/2*time,
500=25/2*time,
500=12.5*time,
500/12.5=time,
Time = 40 second.
Lavi chaudhary said:
7 years ago
@All.
First of all, 360*5/18=1800/18=100 and finally 140-100=40 ans.
First of all, 360*5/18=1800/18=100 and finally 140-100=40 ans.
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