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 9 of 24.
Aditya gangwar said:
1 decade ago
Because both trains are of equal length, mentioned in question. So lets take length=x, then to cross another train of same length i.e. x. First train have to cover distance of x+x.
Thats why he has taken 2x.
Thats why he has taken 2x.
Manish barthwal said:
1 decade ago
It should be mentioned that the faster train started behind the slower train.
If both trains are started at same place then we do not get 2x, because faster train only cover x area which is his own length.
If both trains are started at same place then we do not get 2x, because faster train only cover x area which is his own length.
Vichu119 said:
1 decade ago
Ya if t trains are running from same starting point above answer is wrong because length of train is 100 meter. If the faster train's front starts from slower train's back then the length of train is 50 mt.
Malli said:
10 years ago
Friends he said it takes 36 sec to cross a train then it means the difference in distance b/n them is x (which is length of train).
So the answer is:
x/(Relative speed) = 36;
x = 100;
Not 50 its wrong.
So the answer is:
x/(Relative speed) = 36;
x = 100;
Not 50 its wrong.
Abhishek said:
8 years ago
Since t1 has covered the other train distance and after crossing the train2 it must be having length same x metres from the starting point of train2. In order to calculate length, we have taken 2x metres.
Krupa said:
1 decade ago
The 2x is bcoz
Let the length of the train a =x
Length of the train b =y since both the trains are equal in length uwe can take
Length of train b as also "x"
So, Distance=x+x=2x
simple :-)
Let the length of the train a =x
Length of the train b =y since both the trains are equal in length uwe can take
Length of train b as also "x"
So, Distance=x+x=2x
simple :-)
Srikanth said:
9 years ago
Faster train 46 km/hr, and small train 36 km/hr then, 46 - 36 = 10 km/hr.
Then, 10 * 5/18 = 25/9.
It crosses 36 seconds then 36 * 9/25 = 12.96m then how it becomes 50 m?
I am confused. please explain
Then, 10 * 5/18 = 25/9.
It crosses 36 seconds then 36 * 9/25 = 12.96m then how it becomes 50 m?
I am confused. please explain
Judah said:
4 years ago
The train should be 100mtr. The solution converts both speeds of the 2 trains to m/s and multiply each m/s by 36 and get the difference of the speed at 36 sec, and that the answer.
Hope it will helps.
Hope it will helps.
(3)
Anonymous said:
1 decade ago
How can we conclude that distance covered is 2x because here both the trains are moving and hence along with covering the distance 2x, they will cover some more distance. Please make this thing clear.
Akshay said:
1 decade ago
Use formula
L=length S=Speed
(L1+L2)/(S1-S2)=Time taken by fast train to cross slow train
Let length of train be x
Relative speed = (46-36) * 5/18 m/s =50/18
(x+x)/(50/18) = 36
2x/50=2
2x=100
x=50.
L=length S=Speed
(L1+L2)/(S1-S2)=Time taken by fast train to cross slow train
Let length of train be x
Relative speed = (46-36) * 5/18 m/s =50/18
(x+x)/(50/18) = 36
2x/50=2
2x=100
x=50.
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