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 2 of 4.
Divya said:
1 decade ago
@Chandana said that if trains are moving in opposite direction we have to take only one train length. But in 23 question we are taking both train speeds? please clarify.
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)
Divya said:
1 decade ago
In different situations we are taking relative speed? in which situations we have to find relative speed? and in which situations we have to assume 'x'.
Justin said:
1 decade ago
Here speed and distance where same so we just need to calculate.
s = d/t which means x = 120/12 = 10 then convert it into Km using 10*18/5 = 36.
s = d/t which means x = 120/12 = 10 then convert it into Km using 10*18/5 = 36.
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)
Nisha said:
1 decade ago
In the previous question we are taking the length of the single train, but in this question we are using both the length. Please clarify?
Srikanth said:
1 decade ago
Distance = 120 m.
Time = 2 sec.
Speed = distance/time.
So =120/12 m/sec.
Then our answer is in km/hr.
So (120/12)*(18/5).
= 36 km/hr.
Time = 2 sec.
Speed = distance/time.
So =120/12 m/sec.
Then our answer is in km/hr.
So (120/12)*(18/5).
= 36 km/hr.
Lambrud sachin said:
9 years ago
Distance = 120 m,
Time = 12 sec, s = ?
So, T = D/S,
=> 12 = 120/s.
s = 120/12,
s = 10m/sec.
Then,
s = 10 * 18/5.
s = 36km/hr.
Time = 12 sec, s = ?
So, T = D/S,
=> 12 = 120/s.
s = 120/12,
s = 10m/sec.
Then,
s = 10 * 18/5.
s = 36km/hr.
Kuldeep singh said:
1 decade ago
Length of train = 120 m.
Time = 12 sec.
Speed = ?
Speed = distance/time.
S = 120/12.
S = 10 m/s.
S = 10*18/5.
S = 36 km/hr.
Time = 12 sec.
Speed = ?
Speed = distance/time.
S = 120/12.
S = 10 m/s.
S = 10*18/5.
S = 36 km/hr.
Rishi said:
9 years ago
(120*18/5) = 432.
The length of train = Speed * Time.
120m = ? * 12 sec.
120/12 = 10 m/s.
So, 10*18/5 => 36 km/hr = Speed.
The length of train = Speed * Time.
120m = ? * 12 sec.
120/12 = 10 m/s.
So, 10*18/5 => 36 km/hr = Speed.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers