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:
494 comments Page 23 of 50.
PRADYUMNA KUMAR DAS said:
1 decade ago
If the man and train in opposite direction then it relative speed is x+5. And speed is x+5=45. =>x=40. Am I right?
Anbu said:
1 decade ago
Just try this 1 sec 5 km/hr means 10 sec is 50 km/hr thats it..
becoz the man running at same time train is moving ..
becoz the man running at same time train is moving ..
Anvesh said:
1 decade ago
l=125m;
s=5*5/18;
t=10s;
l=t*s;
s=t/l;
s=125/10;
s=12.5*18/5;
the man was also going same direction so,
s=45+5;
s=50;
s=5*5/18;
t=10s;
l=t*s;
s=t/l;
s=125/10;
s=12.5*18/5;
the man was also going same direction so,
s=45+5;
s=50;
Akansha said:
1 decade ago
18/5 is used to change meter per second to kilometer per hour.
And I have no idea why it says -5 as it should be +5.
And I have no idea why it says -5 as it should be +5.
Priya said:
1 decade ago
To convert kilo meter/hour to meter/sec we consider 5/18.
To convert meter/sec to kilometer/hour we consider 18/5.
To convert meter/sec to kilometer/hour we consider 18/5.
Raja said:
2 decades ago
Thank you friends I understood well never before.
Every one has given their own ideology with respect to problem.
Every one has given their own ideology with respect to problem.
Rohit said:
8 years ago
Whenever we have to convert seconds or minutes to an hour then multiply by 18/5 and if to do vice versa then 5/18.
Dhivya said:
8 years ago
L(train) = (speed of train-speed of object) * time.
125m = (St-5)km/hr * 10s,
112.5 * 18/5 = st - 5,
St = 50km/hr.
125m = (St-5)km/hr * 10s,
112.5 * 18/5 = st - 5,
St = 50km/hr.
Narendran Sainathan said:
8 years ago
18/5 is to convert meter per second to kilo meter per hour. Or you can also use 3600 (seconds)/1000 (kilometre).
Umair chudhary said:
2 decades ago
If someone feel difficult to understand 5/18 i.e; m/s
To convert kmph to mps 1000/60*60 m/s
It is same thing.
To convert kmph to mps 1000/60*60 m/s
It is same thing.
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