Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 23)
23.
Two trains are running in opposite directions with the same speed. If the length of each train is 120 metres and they cross each other in 12 seconds, then the speed of each train (in km/hr) is:
Answer: Option
Explanation:
Let the speed of each train be x m/sec.
Then, relative speed of the two trains = 2x m/sec.
| So, 2x = | (120 + 120) |
| 12 |
2x = 20
x = 10.
 Speed of each train = 10 m/sec = |
 |
10 x | 18 |  |
km/hr = 36 km/hr. |
| 5 |
Discussion:
38 comments Page 1 of 4.
Saanvi S said:
2 years ago
S = D/S.
S = 120/12.
Therefore; S = 10 m/sec.
S = 10 × 18/5
And S = 36 kmph.
S = 120/12.
Therefore; S = 10 m/sec.
S = 10 × 18/5
And S = 36 kmph.
(6)
Keerthi said:
3 years ago
Let the speed of a single train be x m/sec.
length= 120m.
Time to cross each other= 12 sec.
There is a formula like,
a+b/u+v = time to cross each other,
(i.e) 120+120/2x = 12,
240/2x = 12,
X = 40.
= 40 * (18/5)hkm/hr,
= 144.
The Speed of each train is,
= 144/2.
= 72.
length= 120m.
Time to cross each other= 12 sec.
There is a formula like,
a+b/u+v = time to cross each other,
(i.e) 120+120/2x = 12,
240/2x = 12,
X = 40.
= 40 * (18/5)hkm/hr,
= 144.
The Speed of each train is,
= 144/2.
= 72.
(1)
Chris said:
4 years ago
speed=distance/time.
speed = 120/20,
then speed = 10 m/sec,
So, 10 x 18 /5.
Then the answer is 36 km/hr.
speed = 120/20,
then speed = 10 m/sec,
So, 10 x 18 /5.
Then the answer is 36 km/hr.
(2)
Mike Lambulila said:
4 years ago
Where is 18/5 coming from?
(3)
K. A. Raju said:
4 years ago
Distance to be covered by each train to cross each other is 60m. (Half of the length of each train).
Then, speed= 60/12 = 5 m/s = 18 km/hr.
Then, speed= 60/12 = 5 m/s = 18 km/hr.
(1)
Stuti said:
5 years ago
S=D/T.
S=120/12= 10m/sec,
=10*(18/5)=36km/hr.
S=120/12= 10m/sec,
=10*(18/5)=36km/hr.
(2)
Siva said:
6 years ago
How 18/5 came?
(1)
Priyanka said:
7 years ago
How the speed of both trains same?
(1)
Koli Jyoti said:
8 years ago
Let the speed of a singe train be x m/sec.
length= 120m.
time= 12 sec,
speed = length/time.
= 120/12.
= 10 m/s.
According to given question, they want speed in km/hr so we will convert it by formula (a*18/5)km/hr.
In our case a is 10m/s.
So
speed=(10*18/5)km/hr,
=36 km/hr.
length= 120m.
time= 12 sec,
speed = length/time.
= 120/12.
= 10 m/s.
According to given question, they want speed in km/hr so we will convert it by formula (a*18/5)km/hr.
In our case a is 10m/s.
So
speed=(10*18/5)km/hr,
=36 km/hr.
Vaibhav said:
8 years ago
Can anyone tell me that answer is asked in km\hr, but the answer given is s\m?
Why?
Why?
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