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.
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.
Venkatesh said:
1 decade ago
I don't get the reason for distance to be covered as 360+140 can any one suggest the reason with pleasure.
Satish said:
1 decade ago
When a train is crossing a bridge means that train is crossing it's own length and the bridge length. If you see at the end of the compartment to be crossed the bridge, the length of the bridge is depending on the train length, if the train is shorter the the time taken to cross the bridge will be lesser and if the train is longer, the time taken to bridge will be larger to cross at the end of the compartment.
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.
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.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers