Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 9)
9.
Two trains are moving in opposite directions @ 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is:
Answer: Option
Explanation:
Relative speed = (60+ 90) km/hr
| = |  |
150 x | 5 |  m/sec |
| 18 |
| = | |
125 | m/sec. |
| 3 |
Distance covered = (1.10 + 0.9) km = 2 km = 2000 m.
| Required time = | |
2000 x | 3 | sec = 48 sec. |
| 125 |
Discussion:
107 comments Page 9 of 11.
Sriram said:
8 years ago
How you take covered distance as 2km?
Sainath said:
8 years ago
Then, What will be the time taken by faster train to cross slower train?
Raghu said:
8 years ago
2km, when converted using formula, gives 5/9 m/s which is giving the wrong answer. Someone please explain this to me.
Pankaj said:
7 years ago
Hi, the time taken by faster train to cross slower & time taken by slower train to cross faster will be same, right?
So why are we using relative speed formula for all the time. We can use a+b/u+v for calculating time.
So why are we using relative speed formula for all the time. We can use a+b/u+v for calculating time.
Sarang said:
7 years ago
Distance =speed*time,
1.10+.9=60+90*time,
2km=150km/h*time,
2000=150*5/18*time,
2000=750/18*time,
2000=41.66*time,
2000/41.66=time,
Time=48 s.
1.10+.9=60+90*time,
2km=150km/h*time,
2000=150*5/18*time,
2000=750/18*time,
2000=41.66*time,
2000/41.66=time,
Time=48 s.
(1)
Tarek said:
7 years ago
Then the time taken by the faster train to cross the slower will be?
(1)
Ram said:
7 years ago
Guys, can anyone explain how 41.6666667 was turn into 125/3?
Shalinwilson said:
7 years ago
No need to convert to m/s.
Because everything in m and h.
Simply relative speed = 60+90 = 150 km/h.
Distance = 1.1+9 = 2 km.
2/150 = .013 hr (in seconds its .013*60 *60 = 48 seconds.
Because everything in m and h.
Simply relative speed = 60+90 = 150 km/h.
Distance = 1.1+9 = 2 km.
2/150 = .013 hr (in seconds its .013*60 *60 = 48 seconds.
(2)
Hsu Hsu said:
6 years ago
Why do you sum the relation speed of the train in the opposite direction?
If direction are same, will you sum?
Please, someone, explain to me, I need help!
If direction are same, will you sum?
Please, someone, explain to me, I need help!
Srinivas said:
6 years ago
Simply, the solution is;
2 km =2000.
=150 * 5/18 is 41.66.
So 2000/41.66 = 48.
2 km =2000.
=150 * 5/18 is 41.66.
So 2000/41.66 = 48.
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