Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 3)
3.
The length of the bridge, which a train 130 metres long and travelling at 45 km/hr can cross in 30 seconds, is:
Answer: Option
Explanation:
| Speed = |  |
45 x | 5 |  m/sec |
= | |
25 | m/sec. |
| 18 | 2 |
Time = 30 sec.
Let the length of bridge be x metres.
| Then, | 130 + x | = | 25 |
| 30 | 2 |
2(130 + x) = 750
x = 245 m.
Video Explanation: https://youtu.be/M_d8WufJWKc
Discussion:
247 comments Page 5 of 25.
Sarvjeet said:
1 decade ago
Length of the train= 130.
Speed of the train = 45km/hr.
time=30sec.
lengthof bridge = x+length of train.
x+length of train = Speed of the train *time.
x+130=45*5/18*30.
x+130 =375
x=375-130
x=245
Speed of the train = 45km/hr.
time=30sec.
lengthof bridge = x+length of train.
x+length of train = Speed of the train *time.
x+130=45*5/18*30.
x+130 =375
x=375-130
x=245
DGEERAJ said:
1 decade ago
Nusrat has right formula to solve this.
Mathsfobia said:
1 decade ago
Nice explanation survjt.
Anshul patel said:
1 decade ago
Amasing solutions and discussion by you guys but 1 thing I got in mind while coming through few examples is that if some1 is new in solving this type of problems then please draw 1 rough imaginary sketch and then try to solve this type of examples I prefer it to be more easy.
Viji said:
1 decade ago
Vijay kumar your explanation is quite simple and understandable. Thank you.
Subramanyam subbu said:
1 decade ago
distance=speed*time
assume length of bridge as x meters
here distance=(length of bridge+length of train)
x+130=45*(5/18)
[ 5/18 indictes conversion of km/hr to m/sec)
we get x= 245 m i.e length of the bridge
assume length of bridge as x meters
here distance=(length of bridge+length of train)
x+130=45*(5/18)
[ 5/18 indictes conversion of km/hr to m/sec)
we get x= 245 m i.e length of the bridge
Vinu said:
1 decade ago
I've a doubt, if the bridge length is greater than the length of the train, then the train need to travel twice it's length + (bridge length-train length) to cross the bridge, why that factor is not considering in this problem?
RITESH said:
1 decade ago
I want to ask a simple question, how was to come 25/2 ? please send this answer ASAP.
Madhu said:
1 decade ago
We should convert km/hr to m/sec, so we should multiply the 45km/hr by 5/18,then we get 25m/sec.
Sara said:
1 decade ago
Total distance of bridge is 45Km/hr*(30/360)hrs =45/12Kms
Distance in metres = (45/12)*100 =375 Metres
Distance covered = 375M -130M =245M
I believe this is the quickest way given the time allocated in such assessments.
Distance in metres = (45/12)*100 =375 Metres
Distance covered = 375M -130M =245M
I believe this is the quickest way given the time allocated in such assessments.
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