Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 24)
24.
Two trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction?
10
12
15
20
Answer: Option
Explanation:

Speed of the first train = ( 120 ( m/sec = 12 m/sec.
10

Speed of the second train = ( 120 ( m/sec = 8 m/sec.
15

Relative speed = (12 + 8) = 20 m/sec.

Therefore Required time = [ (120 + 120) ] sec = 12 sec.
20

Discussion:
22 comments Page 2 of 3.

Priya said:   8 years ago
Why are we not calculate this way,

s = 120+120/10+15,
= 9.6 m/s.

Correct me if I am wrong.
(1)

Sarika said:   2 decades ago
Two trains running in opposite directions means they come towords each other.

Shweta said:   6 years ago
Why didn't we take (15+10) directly as speed like we add in other questions.
(1)

Akhilesh said:   9 years ago
Anyone can explain this problem? because I'm not understand this problem.

Sam said:   6 years ago
This problem should tell us,two trains are coming from opposite sid.
(1)

Siddharth Kapoor said:   2 decades ago
How can 2 trains running in opposite direction cross each other!!!!

Diya said:   1 decade ago
I am not clear with this problem. Can anyone please explain.

AUNRAJ JAGTAP said:   7 months ago
Very nice, Thanks for explaining the answer.

Shree said:   7 years ago
Thank you all for explaining the answer.

Sudharsan madurai said:   1 decade ago
Average of 10+15 = 12.5.

Almost = 12.


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