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 18 of 25.
Rekha said:
9 years ago
Hii @Sai.
Why did you subtract the two things that is length and speed?
Why did you subtract the two things that is length and speed?
Maanvi said:
9 years ago
@Naveen Kumawat.
Nice description to understand the problem.
Nice description to understand the problem.
Nowsath said:
9 years ago
I have a simple method.
45 * 5/18 equal 12.5 m/s.
Then,
12.5 = x + 130/30 then,
12.5 * 30 = 375.
So,
375 - 130 = 245.
Therefore, x equal 245.
45 * 5/18 equal 12.5 m/s.
Then,
12.5 = x + 130/30 then,
12.5 * 30 = 375.
So,
375 - 130 = 245.
Therefore, x equal 245.
Sandeep said:
9 years ago
It is easy,
Train length = 130mtr,
Speed = 45km/hr,
Time = 30sec.
First:-
Converting the speed:- 45*5/18 = 12.5,
Then, total distance = speed * time.
= 12.5 * 30 = 375.
Therefore, the length of bridge = 375 - 130 = 245.
Train length = 130mtr,
Speed = 45km/hr,
Time = 30sec.
First:-
Converting the speed:- 45*5/18 = 12.5,
Then, total distance = speed * time.
= 12.5 * 30 = 375.
Therefore, the length of bridge = 375 - 130 = 245.
Sidhartha said:
9 years ago
The train has to cover twice it's own length and the length of the bridge to cross the bridge so the answer provided is wrong.
It has to be 2x + 130 = 375.
Hence 2x = 245.
X = 122.50m = length of the train.
It has to be 2x + 130 = 375.
Hence 2x = 245.
X = 122.50m = length of the train.
Emme Naresh said:
9 years ago
Distance = speed/time;.
Let us bridge length = x say, train travelling distance = 130 m.
The total distance is = x + 130,
Speed = 25/2; time = 30sec.
X + 130 = (25/2) 30,
X = 375 - 130 = 245.
Let us bridge length = x say, train travelling distance = 130 m.
The total distance is = x + 130,
Speed = 25/2; time = 30sec.
X + 130 = (25/2) 30,
X = 375 - 130 = 245.
Gaurav rana said:
9 years ago
Why 130 is added to it?
Mahi said:
9 years ago
But here, how do you get 5/18?
Janani said:
9 years ago
How get 5/18?
Kavya said:
9 years ago
Why are you using '130 + x' ?
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