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:
111 comments Page 3 of 12.
Vijju said:
10 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.
(1)
Mainul Bangladesh Khilkhet said:
9 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)
Sarang said:
9 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:
8 years ago
Then the time taken by the faster train to cross the slower will be?
(1)
Hsu Hsu said:
7 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!
(1)
Nanda said:
1 year ago
Please explain the answer.
(1)
Jay Panchal said:
3 months ago
S = 90+60 = 150km/h.
D = 1.10+0.9 km = 2.0 km.
T = D/S.
So, T = (2/150) * 3600(to convert into sec).
D = 1.10+0.9 km = 2.0 km.
T = D/S.
So, T = (2/150) * 3600(to convert into sec).
(1)
Nandy said:
2 decades ago
Time=length/speed
required time=(2000/(125/3))
which is equal to=2000*(3/125)
required time=(2000/(125/3))
which is equal to=2000*(3/125)
CHANDRU said:
2 decades ago
Train moving in opposite direction why are you adding?
Deepti said:
2 decades ago
In opposite direction speed are summed up and in same direction speed are subtracted.
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