Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 7)
7.
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:
Answer: Option
Explanation:
Let the length of each train be x metres.
Then, distance covered = 2x metres.
Relative speed = (46 - 36) km/hr
| = |  |
10 x | 5 |  m/sec |
| 18 |
| = | |
25 | m/sec |
| 9 |
 |
2x | = | 25 |
| 36 | 9 |
2x = 100
x = 50.
Discussion:
232 comments Page 2 of 24.
Chandini said:
2 years ago
Why we take 2x/36=25/9?
Can anyone please explain?
Can anyone please explain?
(9)
Abhishek said:
3 years ago
Why you have done, 2x/36 = 25/9?
And why not 2x/46 = 25/9?
Please explain me clearly.
And why not 2x/46 = 25/9?
Please explain me clearly.
(8)
Pavani said:
1 week ago
The Length of L1 = length of L2.
L1 = L2.
So, length=2L.
Speed of the train t1 = 46km/hr.
Speed of the train t2 = 36km/hr.
The relative speed = t1 - t2 = 46 - 36 = 10km/hr.
convert to meters a = 10x5/18.
Then time = 36sec.
Now using formula:
2L = 10x5/18 x36.
2L = 100,
L = 50m.
L1 = L2.
So, length=2L.
Speed of the train t1 = 46km/hr.
Speed of the train t2 = 36km/hr.
The relative speed = t1 - t2 = 46 - 36 = 10km/hr.
convert to meters a = 10x5/18.
Then time = 36sec.
Now using formula:
2L = 10x5/18 x36.
2L = 100,
L = 50m.
(7)
Basavaraj said:
4 years ago
Answer is 100mtr.
As per the relative speed concept and as per the given question both trains of equal length are at the same point so a faster train has crossed its own length or the length of another one to cross it completely.
So it has to travel x mtr to cross another one with a speed of 10km/hour more.
As per the relative speed concept and as per the given question both trains of equal length are at the same point so a faster train has crossed its own length or the length of another one to cross it completely.
So it has to travel x mtr to cross another one with a speed of 10km/hour more.
(6)
Nishanth said:
2 years ago
It is correct 100m is the answer, but the trains are each length, the faster has to cross the slower train and the Faster train itself so, we divide it by 2 (2 trains).
(6)
Joy khwaka said:
2 years ago
I know most of us are not understanding how 2x/36 comes,
Here is my explanation;
Here 2x is the distance, then 36 is time in seconds.
Here is my explanation;
Here 2x is the distance, then 36 is time in seconds.
(5)
Rudraksha Tyagi said:
4 months ago
In most train problems, especially with same-direction motion, "passes" implies overtaking (faster train starts behind) , leading to 2L.
Am I right?
Am I right?
(5)
Xyz said:
4 months ago
Length of the train = x.
As both train of equal length = 2x,
Relative speed(faster train-slower train) = (46 - 36) = 10km/hr,
To convert km/hr->m/sec,
10*5/18=25/9 in m/sec.
distance travelled = speed * time.
25/9 * 36 = 100m,
As the total distance covered by both the train is 2x,
2x = 100.
And x = 50(length of each train).
As both train of equal length = 2x,
Relative speed(faster train-slower train) = (46 - 36) = 10km/hr,
To convert km/hr->m/sec,
10*5/18=25/9 in m/sec.
distance travelled = speed * time.
25/9 * 36 = 100m,
As the total distance covered by both the train is 2x,
2x = 100.
And x = 50(length of each train).
(5)
Roshan Kunwor said:
3 years ago
Because, when the faster train just crosses the slower, they should cover 2x distance since the length of the train is same.
(4)
Abdul said:
5 years ago
You can easily understand by assuming that one train is a brigde and its length is same as the train, let it be x and the speed of train is 10km/h (46-36).
Now, the time taken to cross the bridge is 36sec.
Dis = speed * time.
= (10*5/18) * 36.
= 100. Is that clear?
We know that 100 is the length of train+length of bridge.
We know both are same so 100÷2 = 50.
Train length is 50 and bridge(another train) length is 50.
Now, the time taken to cross the bridge is 36sec.
Dis = speed * time.
= (10*5/18) * 36.
= 100. Is that clear?
We know that 100 is the length of train+length of bridge.
We know both are same so 100÷2 = 50.
Train length is 50 and bridge(another train) length is 50.
(3)
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