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 47 of 48.
Pravin said:
5 years ago
Thank you @Chandhan Azad.
Ruchitha said:
5 years ago
Why did we take x-5 for the speed? Explain it.
Naresh said:
5 years ago
Trian length/trainspeed - man speed = time.
So, 125/(x-5) * 5/18 = 10.
125 * 18/(x-5)5 = 10
X-5 = 45.
X = 50.
So, 125/(x-5) * 5/18 = 10.
125 * 18/(x-5)5 = 10
X-5 = 45.
X = 50.
Charanjeet pal said:
5 years ago
Why divide 18/5? Please explain.
Sai krishna. B said:
5 years ago
Why 60*60/1000 came here? Can you please explain?
Dinesh kumar said:
5 years ago
The speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr.
Please explain it, friends.
Please explain it, friends.
Wanbok Rabon said:
5 years ago
How get 18/5?
Yash said:
5 years ago
Why they have done 125/10?
Chemayek said:
5 years ago
Good explanation. Thanks all.
Tushar Patil said:
5 years ago
First we write Data:
We Have D=125m t=10s,
S=D/t =125/10=25/2 m/s.
We want to convert from m/s to km/kr.
so we multiply 25/2 into 18/5,
@When we convert km/hr to m/s we multiply by 5/18,
@When we have to convert m/s to km/hr we multiply by 18/5,
Our answer are given in km/hr so we convert according_to by multiplying 18/5.
=25/2*18/5=45 Km/hr,
let we assume train speed be X.
And Man 5 km/hr.
If given in opposite direct then we add,
Here have in the same direction so we subtract,
x-5=45 So Answer is 50.
We Have D=125m t=10s,
S=D/t =125/10=25/2 m/s.
We want to convert from m/s to km/kr.
so we multiply 25/2 into 18/5,
@When we convert km/hr to m/s we multiply by 5/18,
@When we have to convert m/s to km/hr we multiply by 18/5,
Our answer are given in km/hr so we convert according_to by multiplying 18/5.
=25/2*18/5=45 Km/hr,
let we assume train speed be X.
And Man 5 km/hr.
If given in opposite direct then we add,
Here have in the same direction so we subtract,
x-5=45 So Answer is 50.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers