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:
475 comments Page 4 of 48.
Preethiammu said:
2 years ago
Very nice, thanks everyone for explaining the answer.
(28)
Berman said:
2 years ago
Distance covered in crossing.
When the train crosses a stationary object or pole or another train.
The distance covered by the train = length of the train.
So, the length of the train is 125 m =distance covered by the train.
and we know that it took 10 sec to pass the man.
Train Speed = speed of man*time taken by the train to pass,
Speed = 5km/hr * 10sec.
Speed = 50km/hr.
When the train crosses a stationary object or pole or another train.
The distance covered by the train = length of the train.
So, the length of the train is 125 m =distance covered by the train.
and we know that it took 10 sec to pass the man.
Train Speed = speed of man*time taken by the train to pass,
Speed = 5km/hr * 10sec.
Speed = 50km/hr.
(262)
Sheital saira said:
2 years ago
@Hemanth sairam.
Why 60 mins and 60 seconds taken there?
Please explain me.
Why 60 mins and 60 seconds taken there?
Please explain me.
(19)
Atharv S Shelar said:
2 years ago
@All.
All asking the same doubt "why it is 18/5 and not 5/18"?
It is because the conversion for m/s to km/hr is 18/5 and for km/hr to m/s is 5/18.
All asking the same doubt "why it is 18/5 and not 5/18"?
It is because the conversion for m/s to km/hr is 18/5 and for km/hr to m/s is 5/18.
(53)
Hemanth Sairam said:
2 years ago
Let's think man is standing like a pole
125mtrs/10 secs = 12.5 mtrs per sec,
Convert seconds to hours;
12.5 mtrs x 60mins x 60 seconds = 45000 mtrs per hr,
= 45kmph.
The man also moving with some speed right, so the train will take some extra speed to cross than the man
So 45+5 = 50kmph actual train speed.
125mtrs/10 secs = 12.5 mtrs per sec,
Convert seconds to hours;
12.5 mtrs x 60mins x 60 seconds = 45000 mtrs per hr,
= 45kmph.
The man also moving with some speed right, so the train will take some extra speed to cross than the man
So 45+5 = 50kmph actual train speed.
(96)
Sourabh said:
2 years ago
Given data :
Length Of the Train 125 meters.
Speed of Man = 5 km/hr
Speed of train = ?
Time = 10 sec.
Distance = Time * Velocity (speed).
125 = 10 × v,
V = 125/10,
V = 25/2 M/sec Now Convert it into Km/hr,
V = 25/2 × 18/5,
V = 45 km/hr.
And given In The Question train And Man Is Traveling in Same Direction.
V = Speed of train - Speed Of Man.
45 = Speed of train - 5.
Speed of train = 45+5.
Speed of train = 50 km/hr.
Length Of the Train 125 meters.
Speed of Man = 5 km/hr
Speed of train = ?
Time = 10 sec.
Distance = Time * Velocity (speed).
125 = 10 × v,
V = 125/10,
V = 25/2 M/sec Now Convert it into Km/hr,
V = 25/2 × 18/5,
V = 45 km/hr.
And given In The Question train And Man Is Traveling in Same Direction.
V = Speed of train - Speed Of Man.
45 = Speed of train - 5.
Speed of train = 45+5.
Speed of train = 50 km/hr.
(179)
Owona Julius said:
2 years ago
How - 5 came? Please explain this step.
(17)
Chinnupradhan said:
2 years ago
S = L/T.
S = 125/10
S = 25/2.
then,
M/sec to km/hr convert.
1km/hr = [1000m/3600sec] = 5/18m/sec,
m/sec = 18/5km/hr.
i.e
(25/2 * 18/5)km/hr,
45km/hr.
Therefore first train x-5 = 45.
X = 50 km/hr.
S = 125/10
S = 25/2.
then,
M/sec to km/hr convert.
1km/hr = [1000m/3600sec] = 5/18m/sec,
m/sec = 18/5km/hr.
i.e
(25/2 * 18/5)km/hr,
45km/hr.
Therefore first train x-5 = 45.
X = 50 km/hr.
(30)
Ashik Multani said:
2 years ago
Given
Length of train = 125m
Speed of man = 5km/hr = 5 * 5/18 = 25/18
Time = 10sec.
Speed = distance/time
Man running in the same direction so;
Let theh speed of the train is x.
speed = x - 25/18;
then by formula;
x - 25/18 = 125/10
x = 125/10 + 25 /18
x = 250/18 sec/m
Then;
convert into km/hr.
speed = 250/18 * 18/5.
speed = 50 => ans.
Length of train = 125m
Speed of man = 5km/hr = 5 * 5/18 = 25/18
Time = 10sec.
Speed = distance/time
Man running in the same direction so;
Let theh speed of the train is x.
speed = x - 25/18;
then by formula;
x - 25/18 = 125/10
x = 125/10 + 25 /18
x = 250/18 sec/m
Then;
convert into km/hr.
speed = 250/18 * 18/5.
speed = 50 => ans.
(45)
Jaimin Patel said:
2 years ago
Let X km/hr be the speed of the train.
Length = 125m = 0.125km.
Relative Speed= (X-5)km/hr (as train and man moving in the same direction hence it is subtracted).
0125/(X-5) = 10/3600.
X = 50km/hr.
Length = 125m = 0.125km.
Relative Speed= (X-5)km/hr (as train and man moving in the same direction hence it is subtracted).
0125/(X-5) = 10/3600.
X = 50km/hr.
(26)
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