Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 22)
22.
Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.
Answer: Option
Explanation:
| Relative speed = | = (45 + 30) km/hr | |||||||
|
||||||||
|
We have to find the time taken by the slower train to pass the DRIVER of the faster train and not the complete train.
So, distance covered = Length of the slower train.
Therefore, Distance covered = 500 m.
 Required time = |
 |
500 x | 6 |  |
= 24 sec. |
| 125 |
Discussion:
81 comments Page 2 of 9.
Kush said:
4 years ago
What length we should consider if it is asked for faster train?
(1)
Sujee said:
4 years ago
Why do we take 500 instead of 1000?
Please anyone explain me.
Please anyone explain me.
(1)
Destello said:
3 years ago
Simple:
Opposite direction (ADD the speed).
45 + 30 = 75 "answer asked in sec then convert it by multiplying 5/18 to 75".
Speed is 125/6 m/sec.
Now distance travelled by each train is its own distance and other train distance,
i.e. 500+500 =1000.
We have speed and distance use the time formula.
T = D/S.
= 1000 * 6/25.
Opposite direction (ADD the speed).
45 + 30 = 75 "answer asked in sec then convert it by multiplying 5/18 to 75".
Speed is 125/6 m/sec.
Now distance travelled by each train is its own distance and other train distance,
i.e. 500+500 =1000.
We have speed and distance use the time formula.
T = D/S.
= 1000 * 6/25.
(1)
Hemanath said:
8 years ago
How to convert into min? Please tell me.
Raju said:
8 years ago
How 125÷6 came in this problem? Please explain.
Nanda Kishor said:
8 years ago
@Raju.
In this problem, the relative speed is 75km/hr.
And to find the answer we have to convert the speed into m/s. So(75*5/18= 125/6m/s).
Hope that this will help you.
In this problem, the relative speed is 75km/hr.
And to find the answer we have to convert the speed into m/s. So(75*5/18= 125/6m/s).
Hope that this will help you.
Ganda said:
8 years ago
Here answer should be 48 explain it with given example let the speed of the first train be 4m/s and second be 1m/s and length of trains be 5/5 m then you should make number line and get two seconds so we must add 5+5 10m and divides by 5m/ (1+4).
Pallavi said:
8 years ago
How 5/18 coming in the problem?
Pallavi said:
8 years ago
The answer is simple. We are converting the 'kilo-meters/hour' value into 'meters/second'.
Let me explain about converting km/hr into m/s in detail.
1 km = 1000 meters.
1 hr = 3600 seconds.
1 km/hr = 1000/3600 m/s
= 10/36 m/s
= 5/18 m/s.
Therefore 1 km/hr = 5/18 m/sec.
Let me explain about converting km/hr into m/s in detail.
1 km = 1000 meters.
1 hr = 3600 seconds.
1 km/hr = 1000/3600 m/s
= 10/36 m/s
= 5/18 m/s.
Therefore 1 km/hr = 5/18 m/sec.
Sarang said:
7 years ago
Distance =speed * time,
500=45+30km/h*time,
500=75*5/18*time,
500=75*.277*time,
500=20.7*time,
Time=500/20.7=24s.
500=45+30km/h*time,
500=75*5/18*time,
500=75*.277*time,
500=20.7*time,
Time=500/20.7=24s.
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