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 6 of 11.
Ramsha said:
1 decade ago
Yes @Vedant, I also get the same answer through the same process.
Atoria M. Horace said:
1 decade ago
I still can't understand how the 5/18 came about.
Prashant said:
1 decade ago
Please clear my doubt.
Let the train pass after t time.
So train has to cover (120+240+x)/45 in t time.
And jogger covers x/9 in t time.
(120+240+x) /45 = x/9.
Answer is 90 sec but logic is correct that they both meet after t time.
Let the train pass after t time.
So train has to cover (120+240+x)/45 in t time.
And jogger covers x/9 in t time.
(120+240+x) /45 = x/9.
Answer is 90 sec but logic is correct that they both meet after t time.
Ram said:
1 decade ago
Answer is 48 sec as jogger also jogs 2.5x distance.
= 360+2.5x/x = 10.
= 360+2.5x = 10x.
= 360 = 7.5x.
= 48 = x.
Hence 48 sec is the answer.
= 360+2.5x/x = 10.
= 360+2.5x = 10x.
= 360 = 7.5x.
= 48 = x.
Hence 48 sec is the answer.
Padma said:
1 decade ago
Question asked about at what time train cross man. Man has no length then why we add track length?
Monica said:
1 decade ago
Why we add track length means because man is running on track? So man gets the track length.
Sushanto said:
1 decade ago
Why (36 x 5/18) is used? How you get 5/18?
Ankush said:
1 decade ago
5/18 we can get like that.
Suppose speed is 10 km/hr so we can say like that.
(10)*1000/3600 m/second, so 1000/3600 will become 5/18.
Suppose speed is 10 km/hr so we can say like that.
(10)*1000/3600 m/second, so 1000/3600 will become 5/18.
Raji said:
1 decade ago
What is the difference between 2nd problem and 10th problem?
Aaditya said:
1 decade ago
For the 1st 240m. Why are calculating the relative speed?
The jogger comes alongside the train after 240m. So, after that the relative speed should be considered. Please explain.
The jogger comes alongside the train after 240m. So, after that the relative speed should be considered. Please explain.
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