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 23 of 24.
RADHESHYAM KAMDE said:
6 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.
Yash said:
6 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.
Pabitra said:
6 years ago
Hello, how do you take 5/18? please explain.
Lavanya said:
6 years ago
How to calculate 2x/36 = 25/9.
Prashant Gupta said:
6 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.
Mahesh ojha said:
6 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.
Bushra Ahmed said:
6 years ago
From where did 100 come?
Bushra Ahmed said:
6 years ago
From where did 100 come?
FERDAOUS HOSSAIN said:
5 years ago
Let, the length of each train is X m.
Both train length is (X+X) =2X m.
Relative speed (46-36) = 10 km/hr=25/9 m/sec.
As per the question,
2X/36 =25/9.
X=50.
Both train length is (X+X) =2X m.
Relative speed (46-36) = 10 km/hr=25/9 m/sec.
As per the question,
2X/36 =25/9.
X=50.
Vikrant said:
5 years ago
We have formula:
If two trains of length a metres and b metres are moving in the same direction at u m/s and v m/s, then:
The time is taken by the faster train to cross the slower train = (a + b)/(u - v) Sec.
- Since two trains are of same length, so distance or(a+b) = 2x
- Time taken to cross slower train = 36 sec
- Speed of first train(u) = 46 kmph
- Speed of second train(v) = 36 kmph
- By applying formula ::
36 = 2x/((46-36)*(5/18)).
x = 50m.
If two trains of length a metres and b metres are moving in the same direction at u m/s and v m/s, then:
The time is taken by the faster train to cross the slower train = (a + b)/(u - v) Sec.
- Since two trains are of same length, so distance or(a+b) = 2x
- Time taken to cross slower train = 36 sec
- Speed of first train(u) = 46 kmph
- Speed of second train(v) = 36 kmph
- By applying formula ::
36 = 2x/((46-36)*(5/18)).
x = 50m.
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