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 3 of 4.
VIDYASAGAR SHARMA said:
1 decade ago
How 18/5 comes?
Yogesh said:
1 decade ago
18/5 why & where command please clarify it?
Joel said:
1 decade ago
Guys here, each train is travelling 120 m so total distance is 240 m.
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.
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.
Irshad said:
1 decade ago
In option no units are given then why should we convert.
Shabi said:
1 decade ago
Length of the each (two) train 2X = 120m.
Therefore for single train, x = 120/2 = 60m.
Find the seconds for single train, 2x = 12sec.
So speed = 6 sec.
Result, speed = D/S, 60/6 m/sec, 10 m/sec.
Convert to km/hr.
10*18/5 = 2*18 = 36 km/hr.
Therefore for single train, x = 120/2 = 60m.
Find the seconds for single train, 2x = 12sec.
So speed = 6 sec.
Result, speed = D/S, 60/6 m/sec, 10 m/sec.
Convert to km/hr.
10*18/5 = 2*18 = 36 km/hr.
Jack said:
1 decade ago
No need to find the relative speed because speed and length of the both train is same.
So, simply find the speed of single train.
120/12 = 10 m/s.
10*18/5 = 36 km/ph.
So, simply find the speed of single train.
120/12 = 10 m/s.
10*18/5 = 36 km/ph.
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.
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?
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