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:
481 comments Page 5 of 49.
Hemanth Sairam said:
3 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:
3 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.
(181)
Owona Julius said:
3 years ago
How - 5 came? Please explain this step.
(17)
Chinnupradhan said:
3 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:
3 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:
3 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)
Rahul agrawal said:
3 years ago
125 m = 10sec
Than 60sec = 125 x 6 = 750m
1hour = 750 x 60 = 45000m (45km/hr) + 5km/hr = 50km/hr.
Than 60sec = 125 x 6 = 750m
1hour = 750 x 60 = 45000m (45km/hr) + 5km/hr = 50km/hr.
(60)
Mohammed Asif said:
3 years ago
The speed of train is 45 km per hour
And relative speed is 50 km per hour.
But in the question only speed of train is asked not the relative speed.
So, please either change the question and mention relative speed or change the answer to option A 45 km per hour which is the speed of train.
And relative speed is 50 km per hour.
But in the question only speed of train is asked not the relative speed.
So, please either change the question and mention relative speed or change the answer to option A 45 km per hour which is the speed of train.
(37)
Osaji Jeff said:
3 years ago
Why was the formula reversed from 5/18 to 18/5? Please explain me.
(29)
Iliyas said:
4 years ago
m/sec = [1/1000 km] / [1/3600 sec]
= [1/1000] *[3600/1],
= [3600/1000].
= [18/5]km/hr.
= [1/1000] *[3600/1],
= [3600/1000].
= [18/5]km/hr.
(28)
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