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 3 of 11.
Ram said:
7 years ago
Guys, can anyone explain how 41.6666667 was turn into 125/3?
Tarek said:
7 years ago
Then the time taken by the faster train to cross the slower will be?
(1)
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)
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.
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.
Sainath said:
8 years ago
Then, What will be the time taken by faster train to cross slower train?
Sriram said:
8 years ago
How you take covered distance as 2km?
Mainul Bangladesh Khilkhet said:
8 years ago
@Vijju.
You are right that we have to consider the faster train's length. But you have to keep concern about that both trains starts from opposite direction. So, both trains cross each others at the same time. So, when they cross each others from the opposite direction; so in that case individual length is not important. But total length of the trains is important to measure the total distance/way what they cross each others.
You are right that we have to consider the faster train's length. But you have to keep concern about that both trains starts from opposite direction. So, both trains cross each others at the same time. So, when they cross each others from the opposite direction; so in that case individual length is not important. But total length of the trains is important to measure the total distance/way what they cross each others.
(1)
Vijju said:
8 years ago
Here we need to consider the only length of faster trains because the question asked for the time taken by slower to pass fast train. So that what I think we need to consider relative speed but faster train length.
Surya said:
9 years ago
2km/150km/hr * 3600.
Answer 48sec.
Answer 48sec.
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