Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 7)
7.
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:
50 m
72 m
80 m
82 m
Answer: Option
Explanation:

Let the length of each train be x metres.

Then, distance covered = 2x metres.

Relative speed = (46 - 36) km/hr

   = 10 x 5 m/sec
18

   = 25 m/sec
9

2x = 25
36 9

2x = 100

x = 50.

Discussion:
232 comments Page 1 of 24.

Raghavendra said:   2 years ago
It's a simple calculation, in the above question mention that is found out the length of each train.

Formula:
Length= speed ×time.
Speed = 46-36 = 10 ×5/18 = 2.7777.
Time = 36 seconds.

Then,
Length = 2.7777 × 36.
Length = 100 m.
Length of each train = 50m.
(99)

Thimothy said:   1 year ago
Let the speed be 46 & 36 kmph are travel in the same direction so (46-36) = 10 Kmph then change in m/s.
So, 10×5/18 = (25/9)M/S
Distance=speed * time.

They asking the length of each train(2 L )
Distance= speed×time
2 L = (25/9) ×36
2 L = 100
L = 50.
(43)

Prity Manna said:   1 year ago
Length of two train = (x + x) = 2x m.
time 36 sec.
Speed = (46-36) = 10 * (5/18) = 25/9 m.
We know that if the train parallel lines in the same direction,
So, t = (L1+L2)/(S1-S2) sec,
so,36 = 2x/(25/9),
2x/36 = 25/9,
18x = 900,
x = 50.
Length of the train is 50 m.
(38)

Ghari said:   2 years ago
The two trains were at race from the same point. One is not behind the other to cross 2x length, so it will be only x length.

Am I right?
(20)

Wanambwa Musa said:   2 years ago
To find the length of each train, you can use the relative speed formula:

Relative Speed = Speed of Faster Train - Speed of Slower Train.
Relative Speed = (46 km/hr - 36 km/hr) = 10 km/hr.
Now, you need to convert the relative speed to meters per second (m/s) because the time is given in seconds:
1 km/hr = 5/18 m/s.

So, 10 km/hr = (10 * 5/18) m/s = (50/18) m/s = (25/9) m/s (approximately)
Now, you can use the formula for distance:
Distance = Speed x Time.
Distance = (25/9) m/s x 36 seconds = (25/9) x 36 meters,
Distance = 100 meters (approximately).
Since the faster train passes the slower train in 36 seconds, the length of each train is 100 meters.
(16)

Sahitya said:   2 years ago
speed of the train 1 = 46km/hr,
speed of the train 2 = 36km/hr,
Relative speed = 46 - 36 = 10km/hr.
t = 36sec.

10 * 5/18 = 50/18 m/sec.
S = d/t.
S = L1 + L2.
Here two trains have equal lengths.
So, its 2L1.
S = 2L1/t.
50/18 = 2L1/36.
L1 = 50m.
So, the length of each train is 50 m.
(15)

Navdeep said:   2 years ago
The answer should be 100.
(13)

Indranil Mal said:   2 years ago
Since the length of the two trains are equal then in 36 seconds the trains cross each other.

Relative speed = 46 - 36 = 10kmph.
In 3600sec distance covered=10000m.
Therefore distance covered in 36 secs=10000/3600 * 36 = 100.
As the train covers each other and the length is of equal.
So the actual length of each train = 100/2 = 50m.
(10)

Mhs said:   12 months ago
The answer should be 100, then how it will be 50? can anyone explain?
(10)

Samreen Sultana said:   2 years ago
= [10*5/18]*36.
= 100.
= √100 = 50.
= 50 is the answer.
(9)


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