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 15 of 48.
Preetha said:
1 decade ago
Hi friends, I can't understand this please anyone help me in some other method.
Gnana said:
1 decade ago
Very nice vandha.
Sagar said:
1 decade ago
Finally we need to find speed me train. But in problem train speed is compared with moving object i.e man. So (total speed of train-speed of man=relative speed).
Pradeep said:
1 decade ago
Can you please explain me what is relative speed here and why it is used here ?
Nagaraj said:
1 decade ago
It should be taken as 1000/60*60 beacuse distance covered/ time taken.
M.kanna said:
1 decade ago
18/5 explanation is super k/m h/r put 1000/3600=5/18 answer is very nice apserve then nice.
Mahendra said:
1 decade ago
Nice explanation sheela thank you all who commented.
Pradeep said:
1 decade ago
From The Question 5Km/hr So please explain it 1000/3600. give me reason.
KIRUBHA said:
1 decade ago
FRNDS is it correct or not tell me plz....
MAN'S SPEED = 5 KM/HR
Train length =125 m.
let assume train speed=x.
then we get relative speed (rs) of train and man is become
rs=x-5.
To conver km/hr into m/s.
= (x-5) / (5/18)
= 5x-25 / 18
speed = distance/time
125/10 = 5x-25 / 18
2250 = 50x-250
x = 2000 / 50
x = 40
Is it correct?
MAN'S SPEED = 5 KM/HR
Train length =125 m.
let assume train speed=x.
then we get relative speed (rs) of train and man is become
rs=x-5.
To conver km/hr into m/s.
= (x-5) / (5/18)
= 5x-25 / 18
speed = distance/time
125/10 = 5x-25 / 18
2250 = 50x-250
x = 2000 / 50
x = 40
Is it correct?
Swapnil....... said:
1 decade ago
Why is it addition of 45km/hr & 5km/hr?
Because I thing train & man is going to same direction that time sutract but in this case addition of 45km/Hr & 5km/hr please explain it why is it addition.
Because I thing train & man is going to same direction that time sutract but in this case addition of 45km/Hr & 5km/hr please explain it why is it addition.
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