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:
234 comments Page 5 of 24.
Mahesh ojha said:
7 years ago
I think it the faster train has started from behind then only the answer is 50 meter. But if they started from the same point then the total distance covered be the only x.
Prashant Gupta said:
7 years ago
Relative length L.R = L1 + L2 = 2L.
Rel. SPEED ... (46- 36)5/18= 10m/s.
Relative Time... T.R =36.
Therefore,
L.R= R.S * R.T.
2L = 10 *36.
L = 50m.
Rel. SPEED ... (46- 36)5/18= 10m/s.
Relative Time... T.R =36.
Therefore,
L.R= R.S * R.T.
2L = 10 *36.
L = 50m.
Lavanya said:
7 years ago
How to calculate 2x/36 = 25/9.
Pabitra said:
7 years ago
Hello, how do you take 5/18? please explain.
Yash said:
7 years ago
What is happening here is that:
Train 1 is running at the speed of 36km/hr.
Now, train 2 which is running at 46km/hr crosses the train 1, means it comes from behind and the whole train goes ahead of train 1.
So, first it travels x distance i.e. length of train1&2 to reach side by side of train 1 and x distance to cross it.
Hence, distance 2x.
Train 1 is running at the speed of 36km/hr.
Now, train 2 which is running at 46km/hr crosses the train 1, means it comes from behind and the whole train goes ahead of train 1.
So, first it travels x distance i.e. length of train1&2 to reach side by side of train 1 and x distance to cross it.
Hence, distance 2x.
RADHESHYAM KAMDE said:
7 years ago
Let the length of first train = L.
As we know that trains has equal length;
Therefore L+L = 2L.
And relative speed = 46-36 km/hr (because of the train are going the same direction, so we substrated it).
= 25/9 m/sec.
Time given in question = 36 sec.
We know;
Speed = distance/time.
25/9 = 2L/36,
L = 50 metre.
As we know that trains has equal length;
Therefore L+L = 2L.
And relative speed = 46-36 km/hr (because of the train are going the same direction, so we substrated it).
= 25/9 m/sec.
Time given in question = 36 sec.
We know;
Speed = distance/time.
25/9 = 2L/36,
L = 50 metre.
Ruchi chaubey said:
7 years ago
How did you take 2x?
Please explain.
Please explain.
Rutvik said:
7 years ago
Please explain 25/9=2.7m/s.
If we use the formula a+b/u-v and if the length is equal then 2a/2.7 = 36.
Which comes to 2a = 36 * 2.7.
i.e.a=36*2.7/2 which comes to 48.6.
Then how it will be 50?
If we use the formula a+b/u-v and if the length is equal then 2a/2.7 = 36.
Which comes to 2a = 36 * 2.7.
i.e.a=36*2.7/2 which comes to 48.6.
Then how it will be 50?
PAVAN said:
7 years ago
How do we get 2x/36 = 25/9?
Subba said:
7 years ago
@Sunny.
We know that speed = distance /time, here apply the same, but here since two trains are moving in the same direction relative speed comes and it is 10km/hr.
Then distance = 10 * 5/18 * 36 = 100metres.
Therefore, 2x = 100 and hence x = 50m each.
We know that speed = distance /time, here apply the same, but here since two trains are moving in the same direction relative speed comes and it is 10km/hr.
Then distance = 10 * 5/18 * 36 = 100metres.
Therefore, 2x = 100 and hence x = 50m each.
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