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 3 of 24.
AMGOTH SRIVASU said:
6 months ago
@All
Speeds of {train1:46km/h},{train2:36km/h}
Across each other in time 36s,
Here the two are in parallel directions travelling where the relative speed of parallel is (train1-train2)/2.
so: length = (t1 - t2)/2 * time.
length= (46km-36km)/2 * 36,
= 10km * 18,
= 10 * (5/18)m*18,
Therefore the length = 50m.
Speeds of {train1:46km/h},{train2:36km/h}
Across each other in time 36s,
Here the two are in parallel directions travelling where the relative speed of parallel is (train1-train2)/2.
so: length = (t1 - t2)/2 * time.
length= (46km-36km)/2 * 36,
= 10km * 18,
= 10 * (5/18)m*18,
Therefore the length = 50m.
(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)
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)
Khushnood Ali said:
2 years ago
Speed = distance/time.
Speed = 2x/36 (2x assumed as distance covered by train and 36secs time is given).
The relative speed = 25/9 (calcuated in solution)
From both equation relative speed and speed should be same that's why;
2x/36 = 25/9.
Speed = 2x/36 (2x assumed as distance covered by train and 36secs time is given).
The relative speed = 25/9 (calcuated in solution)
From both equation relative speed and speed should be same that's why;
2x/36 = 25/9.
(3)
Yoo said:
4 months ago
The Length of the train be x.
(u-v) = 46 - 36 = 10km/hr = 25/9,
T = (a+b)/(u-v).
T is the time difference of 36 sec.
(u-v)relative speed train moves in the same direction.
By Substitute all values;
36 = (x+x)/(25/9),
36 * 25/9 = 2x,
x = 50.
(u-v) = 46 - 36 = 10km/hr = 25/9,
T = (a+b)/(u-v).
T is the time difference of 36 sec.
(u-v)relative speed train moves in the same direction.
By Substitute all values;
36 = (x+x)/(25/9),
36 * 25/9 = 2x,
x = 50.
(3)
Shri.. said:
3 years ago
@Bushra Ahmed.
2x=25/9*36 = 900/9 = 100.
2x=25/9*36 = 900/9 = 100.
(2)
Aditya said:
6 months ago
@SRIRAM.
We have to add both train lengths assume with your hand both hands cross each other now slow the process when your left hand and right hand meet the length of your left-hand and right-hand not subtract.
We have to add both train lengths assume with your hand both hands cross each other now slow the process when your left hand and right hand meet the length of your left-hand and right-hand not subtract.
(2)
Shyam said:
1 decade ago
How can we take 2X there?
(1)
Madhav said:
6 years ago
Since they are moving in same direction relative speed is;
46-36=10Km/h= 10*(5/18)= 2.77m/s.
Relative Speed is =2.77m/s.
Speed=Distance/Time.
Distance=Speed*time=2.77*36=99.9==100.
Here 2 train having equal length = D=L=l+l=2l.
2l=100
so l=50.
46-36=10Km/h= 10*(5/18)= 2.77m/s.
Relative Speed is =2.77m/s.
Speed=Distance/Time.
Distance=Speed*time=2.77*36=99.9==100.
Here 2 train having equal length = D=L=l+l=2l.
2l=100
so l=50.
(1)
Mahesh Kariya said:
6 years ago
((46-36)X(5/18)) = (50/18) = (100/36).
2X = 100.
X = 50.
2X = 100.
X = 50.
(1)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers