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 5 of 11.
Nandhu said:
9 years ago
Speed = 60 + 90.
= 150km/hr.
Length = 1.1 + 0.9.
= 2km.
Time = length/speed.
= 2/150,
= 1/75 hr (1 hr=3600s),
= 3600/75 s,
= 48sec.
= 150km/hr.
Length = 1.1 + 0.9.
= 2km.
Time = length/speed.
= 2/150,
= 1/75 hr (1 hr=3600s),
= 3600/75 s,
= 48sec.
Dipti said:
1 decade ago
Relative speed = (60+ 90) km/hr 150 is ok
= 150 x 5/18 m/sec
but how this 5/18 came
could you please discuss on this
= 150 x 5/18 m/sec
but how this 5/18 came
could you please discuss on this
Rajkumar said:
1 decade ago
You all use this formula and do the sum.
The sum which is in opposite direction.
So, formula for time=(L1+L2)/(S1+S2)sec
The sum which is in opposite direction.
So, formula for time=(L1+L2)/(S1+S2)sec
Vaideki said:
1 decade ago
HI Raj good job .its an easy way to find the answer.Same direction means (x+y)/(u-v) if it opposite means (x+Y)/(u+v)
B.K.S said:
9 years ago
Length should always be added irrespective of direction and both trains are passing each other in same time interval.
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.
Ram said:
1 decade ago
They are starting at two different points and moving in opposite direction. They are not starting at the same point.
Kiran said:
1 decade ago
But can you tell me when we subtract (1.10km-0.9km)it becomes(0.2km)
then how can it becomes 2 km. Please explain.
then how can it becomes 2 km. Please explain.
God Here said:
7 months ago
@All.
Here's the solution:
Total distance = 2km;
total speed = 150;
time in seconds = (2/150)x3600 = 48 Answer.
Here's the solution:
Total distance = 2km;
total speed = 150;
time in seconds = (2/150)x3600 = 48 Answer.
(9)
Arulmozhi said:
1 decade ago
When the two trains moving towards or in opposite direction that time we find relative speed.
Am I correct?.
Am I correct?.
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