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 7 of 8.
Gaurav said:
1 decade ago
Total length = bridge length + train length = 140+360=500.
Let time taken by train be x.
Then,
500/x=45*5/18 m/sec.
500/x=25/2.
1000=25x.
x=40 sec answer.
Let time taken by train be x.
Then,
500/x=45*5/18 m/sec.
500/x=25/2.
1000=25x.
x=40 sec answer.
Swayoni said:
1 decade ago
Why the distance is calculated as (360+140) ? why not only 360?
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:
2 decades 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.
Paddy said:
2 decades ago
5/18 comes .because we want to express the unit of speed to m/s
1km/hr=1000m/3600s=5/18 m\s
1km/hr=1000m/3600s=5/18 m\s
Sikkanthar said:
1 decade ago
It is very simple problem.
Here we are going to calculate the value of the time.
All we know the distance or length is nothing but (train length + platform length) from this value we can calculate the time value like.
Length/speed = time.
Convert the speed value m/s into kmph.
Here we are going to calculate the value of the time.
All we know the distance or length is nothing but (train length + platform length) from this value we can calculate the time value like.
Length/speed = time.
Convert the speed value m/s into kmph.
Yash said:
1 decade ago
The Distance travelled by train + bridge length should divide with speed. Simple logic.
Vinod Anand said:
1 decade ago
Total Length of Train and Bridge = 360+140 = 500 Mtr.
And Speed is = 45km/hr.
Than T = 500*18/45*5.
= 200/5.
= 40 sec.
And Speed is = 45km/hr.
Than T = 500*18/45*5.
= 200/5.
= 40 sec.
Shrif said:
1 decade ago
This answer will getting by converting the values of distance and cross multiplication to get this answer easily.
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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