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:
254 comments Page 22 of 26.
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.
Mathsfobia said:
1 decade ago
Nice explanation survjt.
DGEERAJ said:
2 decades ago
Nusrat has right formula to solve this.
Sarvjeet said:
2 decades 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
Rajeev R T said:
2 decades ago
If the train is travelling 45 km per hr, then in one min.it can travel 750m, and in 1 sec it can travel 12.5m. then in 30 sec it can travel 375.00 m. As in 375m the length of the train is included, deduct the length of the train from the 375.00m, i.e 245.00m.
Mukesh said:
2 decades ago
Given.....
train = 130m
speed = 45 km/hr or (75/6)m/s
time to cross bridge=30sec
Bcos the time is in sec thtat why we convert time in m/sec by multiplying and dividing 45 by 1000 and 3600 respectively
simple formula is distance=speed x time
=(75/6) x 30
=375 meters
now this distance is the distance which include train length also so less train length from this
=375-130
=245 meters
hence we get the ans
train = 130m
speed = 45 km/hr or (75/6)m/s
time to cross bridge=30sec
Bcos the time is in sec thtat why we convert time in m/sec by multiplying and dividing 45 by 1000 and 3600 respectively
simple formula is distance=speed x time
=(75/6) x 30
=375 meters
now this distance is the distance which include train length also so less train length from this
=375-130
=245 meters
hence we get the ans
Lokesh said:
2 decades ago
Actually bridge is a stationary object rite. So speed should be zero. Can u pls explain
Mannsoorkhan said:
2 decades ago
sai your explanation is clear and better explanation thanks to all
Nathy said:
2 decades ago
Sai's method of solving this problem is too simple and easy to understand. Thanks.
Rohit said:
2 decades ago
For just above explanation, bridge end point means, departure point of bridge.
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