Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 2)
2.
A train 125 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is:
Answer: Option
Explanation:
| Speed of the train relative to man = |  |
125 |  m/sec |
| 10 |
| = | |
25 | m/sec. |
| 2 |
| = | |
25 | x | 18 | km/hr |
| 2 | 5 |
= 45 km/hr.
Let the speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr.
x - 5 = 45 
x = 50 km/hr.
Discussion:
478 comments Page 6 of 48.
Raghu k said:
4 years ago
It is simple guys.
If we observe hint, her there should be the relative speed because the train and are travelling in the same direction so we (train) -v (man) T =Distance.
(120/10) (18/5) =v (t) -5.
45+5=v (t).
50=v (t).
If we observe hint, her there should be the relative speed because the train and are travelling in the same direction so we (train) -v (man) T =Distance.
(120/10) (18/5) =v (t) -5.
45+5=v (t).
50=v (t).
(8)
Kushal M V said:
4 years ago
They took 18/5 because the length of train is in meter and time given which passes the man is given in seconds. To convert m/s to km/ hr they multiplied with 18/5. And the answers also in km/hr.
(2)
Kushal M V said:
4 years ago
They took 18/5 because the length of train is in meter and time given which passes the man is given in seconds. To convert m/s to km/ hr they multiplied with 18/5. And the answers also in km/hr.
Bithal Jena said:
4 years ago
Solution:
Time = Distance/Speed.
Length of train=125m.
Speed of the person in the same direction is 5KM/hr i.e 25/18m/sec
the train takes 10 sec to cross i.e our time.
Let take x as the speed of the train.
So according to the above formula.
10 = 125/x-(25/18),
10 = 125 * 18/18x-25.
x = 13 * 18/5 m/sec.
To make it KM/hr we have to multiply it by the help of 18/5.
13*18/5 * 18/5 = 46km/hr.
So ans should be 46.
Time = Distance/Speed.
Length of train=125m.
Speed of the person in the same direction is 5KM/hr i.e 25/18m/sec
the train takes 10 sec to cross i.e our time.
Let take x as the speed of the train.
So according to the above formula.
10 = 125/x-(25/18),
10 = 125 * 18/18x-25.
x = 13 * 18/5 m/sec.
To make it KM/hr we have to multiply it by the help of 18/5.
13*18/5 * 18/5 = 46km/hr.
So ans should be 46.
(3)
Abinaya said:
4 years ago
Why we should reciprocal 5/18 to 18/5? Please explain.
Seshu said:
4 years ago
length = speed * time = 5 * 10 = 50.
(3)
Suraj kale said:
4 years ago
The object Man is also moving in the same direction as that of the train so the total distance covered should not be 125 meters.
It should be the (125+X).
Where X is the distance covered by man in 10 seconds.
It should be the (125+X).
Where X is the distance covered by man in 10 seconds.
Nilesh838 said:
4 years ago
Good explanation, thanks.
Naveen said:
4 years ago
I can't understand this sum please anyone explain me briefly.
Namith said:
4 years ago
What is the difference between the relative speed of train and the speed of the train? Anyone, please explain.
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