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 3 of 8.
Dwaraka said:
2 decades ago
Hi rajasekaran the solution
speed=55km/hr
= (55*1000)/(60*60)
=15.27m/s
Total distance=the bridge distance+distance of the train to cross the bridge
d=470+140=610
time=d/s=610/15.27=39.94s
speed=55km/hr
= (55*1000)/(60*60)
=15.27m/s
Total distance=the bridge distance+distance of the train to cross the bridge
d=470+140=610
time=d/s=610/15.27=39.94s
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.
Pavani_reddy said:
1 decade ago
Hi divya.........
Here all ans's are in seconds so we hav to convert km/hr to m/sec
So
1km=1000m
1hr=3600s
1km/hr=1000/3600 m/s
1km/hr=5/18m/sec
Have a nice day guys.................
Here all ans's are in seconds so we hav to convert km/hr to m/sec
So
1km=1000m
1hr=3600s
1km/hr=1000/3600 m/s
1km/hr=5/18m/sec
Have a nice day guys.................
Sundar said:
2 decades ago
Hi Naveen,
Time = Distance / Speed
Here,
Distance = 500 m.
Speed = 25/2
Therefore, Time = 500/ (25/2)
Time = 500/12.5 = 40 sec.
or
Time = 500 x 2 / 25 = 40 sec.
Time = Distance / Speed
Here,
Distance = 500 m.
Speed = 25/2
Therefore, Time = 500/ (25/2)
Time = 500/12.5 = 40 sec.
or
Time = 500 x 2 / 25 = 40 sec.
(1)
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?
Aakriti said:
5 years ago
@Sreee,
According to question, the train should cross the bridge ie. 360m long train should cross 140m long bridge.
Hence, we should add 360 and 140 for total length.
According to question, the train should cross the bridge ie. 360m long train should cross 140m long bridge.
Hence, we should add 360 and 140 for total length.
(6)
Rajkumar velu said:
1 decade ago
Hi saranya,
When the two length is there,
We use the formula for time=(length1+length2)/speed
Speed=45*5/18=25/2 m/sec
So, t=(360+140)/25/2
t=500*2/25
t=40 sec
When the two length is there,
We use the formula for time=(length1+length2)/speed
Speed=45*5/18=25/2 m/sec
So, t=(360+140)/25/2
t=500*2/25
t=40 sec
Ramashish mallah said:
2 decades ago
Thank You.
Rahul, You explained very well and cleared all my confusing.
I am greatful to you.
Regards,
Ramashish Mallah
ramashish.mallah[at]gmail.com
Rahul, You explained very well and cleared all my confusing.
I am greatful to you.
Regards,
Ramashish Mallah
ramashish.mallah[at]gmail.com
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.
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.
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