Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 10)
10.
A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger?
Answer: Option
Explanation:
Speed of train relative to jogger = (45 - 9) km/hr = 36 km/hr.
| = |  |
36 x | 5 |  m/sec |
| 18 |
= 10 m/sec.
Distance to be covered = (240 + 120) m = 360 m.
 Time taken = |
|
360 | sec |
= 36 sec. |
| 10 |
Discussion:
106 comments Page 3 of 11.
Karthik said:
7 years ago
Why relative speed covered entire distance. I suspect that when train engine enter to jogger after that we should consider relative speed?
Please explain anyone.
Please explain anyone.
Kavya said:
7 years ago
Why didn't we use relative speed formula here instead why we did use the speed of train relative to jogger?
Please explain me.
Please explain me.
MasterMind said:
7 years ago
Same direction,
d1+d2=240+120,
d=360,
speed :(same direction,)
s1-s2=45-9=36kmph.
36*5/18=10m/s,
therefore,
assume time=x,
d=speed*time ,
360=10*(x).
36 = x.
d1+d2=240+120,
d=360,
speed :(same direction,)
s1-s2=45-9=36kmph.
36*5/18=10m/s,
therefore,
assume time=x,
d=speed*time ,
360=10*(x).
36 = x.
Jime said:
7 years ago
Why do we add the distance with direction?
Afreen said:
7 years ago
For same direction,
t=l1+l2/s1-s2.
t=l1+l2/s1-s2.
(1)
Vivek Manve said:
7 years ago
Jogger is also running. So he will cover some distance, that should be taken in calculation right?
Shubhangi nema said:
7 years ago
A jogger is a point object so why we consider the platform length?
Pratik said:
7 years ago
@All.
I have a doubt. The jogger was not static. This means he/she must have covered some distance before the train crosses, all the solutions have not included this issue. Should I neglect that distance or is there anything I am missing.
To me, total distance = train length+ 240 metre+ the joggers covered path.
Is that correct or not. If not please help.
I have a doubt. The jogger was not static. This means he/she must have covered some distance before the train crosses, all the solutions have not included this issue. Should I neglect that distance or is there anything I am missing.
To me, total distance = train length+ 240 metre+ the joggers covered path.
Is that correct or not. If not please help.
Gokul said:
7 years ago
Here the equation is (l1+l2)/(v2+v1).
Mayur said:
7 years ago
Why we are considering full length of the platform as 240m?
It is very much possible that the train will cross the jogger before the platform (240m) is fully covered.
Then why total distance= 120m+240m?
It is very much possible that the train will cross the jogger before the platform (240m) is fully covered.
Then why total distance= 120m+240m?
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