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 2 of 8.
Amaran said:
1 decade ago
Train distance is = 360m long.
Speed of the train is = 45km/hr.
Changing into m/second = (45*5/18) m/hr.
The platform distance is = 140m.
Both the distance = 500m.
Speed = distance/time.
Time = distance/speed.
Time = 500*18/5*45.
Time = 40sec.
Speed of the train is = 45km/hr.
Changing into m/second = (45*5/18) m/hr.
The platform distance is = 140m.
Both the distance = 500m.
Speed = distance/time.
Time = distance/speed.
Time = 500*18/5*45.
Time = 40sec.
Priya said:
1 decade ago
@ Dwaraka.
Regarding this prob (A train 470 m long is running at a speed of 55 km/hr. In what time will it pass a bridge 140 m long?).
I understood the solution but it ll take quit time to solve. Can you please provide some shortcut trick to solve.
Regarding this prob (A train 470 m long is running at a speed of 55 km/hr. In what time will it pass a bridge 140 m long?).
I understood the solution but it ll take quit time to solve. Can you please provide some shortcut trick to solve.
Sarvepalli.rajasekhar said:
1 decade ago
Speed = 45 km / hr = 45 x 1000 / 3600 = 25/2 meters per second.
Total Length = Length of train + bridge = 360+140 = 500 meters.
Time = ?
speed = distance / time
25 / 2 = 500 / y
25/2 x y = 500
y = 500 / (25/2) = 500 x 2/25 = 1000/25 = 40 seconds.
Total Length = Length of train + bridge = 360+140 = 500 meters.
Time = ?
speed = distance / time
25 / 2 = 500 / y
25/2 x y = 500
y = 500 / (25/2) = 500 x 2/25 = 1000/25 = 40 seconds.
ANIL said:
7 years ago
Given,
length of the train =360m,
speed of train =45km/h,
length of the bridge =140m,
time =T.
Now convert 45km/h=45*5/18=225/18m/s.
Total length=360m+140m=500m.
We know speed =distance/time.
=> 225/18=500/T.
=> T=500*18/225.
=> T=40s.
length of the train =360m,
speed of train =45km/h,
length of the bridge =140m,
time =T.
Now convert 45km/h=45*5/18=225/18m/s.
Total length=360m+140m=500m.
We know speed =distance/time.
=> 225/18=500/T.
=> T=500*18/225.
=> T=40s.
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?
Rahul kulkarni said:
2 decades ago
Do not go for complication.
Convert 45km to m i.e. 45000m & 1hr=3600sec.
Then, 45000/3600sec. therefore 12.5m/sec. Total distance to be covered is
360m + 140m = 500m
Then, time required to pass the bridge is 500m/12.5m/s = 40sec.
Convert 45km to m i.e. 45000m & 1hr=3600sec.
Then, 45000/3600sec. therefore 12.5m/sec. Total distance to be covered is
360m + 140m = 500m
Then, time required to pass the bridge is 500m/12.5m/s = 40sec.
Paschal said:
2 years ago
For a train to cover any distance, I believe it must first cover(move) its length, that is why we have to add the train length (distance) and that bridge which is static which also the train has to cover.
Correct me If I am wrong.
Correct me If I am wrong.
(9)
Issacnewton said:
1 decade ago
Hi everybody,
See when a train crosses a platform/bridge, it (train) has to cross.
The length of the platform/bridge as well as its own length4.
Length of the train+platform we should take to solve the problem.
See when a train crosses a platform/bridge, it (train) has to cross.
The length of the platform/bridge as well as its own length
Length of the train+platform we should take to solve the problem.
Saranya said:
1 decade ago
Hi,
Me too having same problem... why we can take total distance... they didn't mentioned anything that to cover total distance... they asked how long it ll take pass 140m long... please can any one explain...
Me too having same problem... why we can take total distance... they didn't mentioned anything that to cover total distance... they asked how long it ll take pass 140m long... please can any one explain...
Sreee said:
5 years ago
Please explain to me why we are adding train length and bridge length. The train is moving on the bridge only.
And they asked only the time taken to move on the bridge.
Please explain to me in detail.
And they asked only the time taken to move on the bridge.
Please explain to me in detail.
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