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 4 of 24.
Bhavithra said:
5 years ago
What is the meaning of relative speed?
Shantanu singh parihar said:
5 years ago
We have 2x cause,
When the faster train passes to slower,
It is covering;
X+X distance(slower train +higher speed train),
So the total distance covered is 2X.
When the faster train passes to slower,
It is covering;
X+X distance(slower train +higher speed train),
So the total distance covered is 2X.
(1)
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)
Md. Habibur Rahman said:
6 years ago
When we calculated relative speed, Why we calculate 2x?
Relative speed means a train will be static. Then we can calculate x only. Am ai right? Please tell me.
Relative speed means a train will be static. Then we can calculate x only. Am ai right? Please tell me.
(1)
Vikrant said:
6 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.
FERDAOUS HOSSAIN said:
6 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.
Mahesh Kariya said:
6 years ago
((46-36)X(5/18)) = (50/18) = (100/36).
2X = 100.
X = 50.
2X = 100.
X = 50.
(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)
Bushra Ahmed said:
7 years ago
From where did 100 come?
Bushra Ahmed said:
7 years ago
From where did 100 come?
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