A train of lenght 384 metres crosses an electric pole in 12 seconds and crosses another train fo the same lenght travelling in opposite direction in 12 seconds. What is the speed of the second train?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 32 m/s
The first train crosses an electric pole = 12 seconds
the speed of the first train = Distance/Time = 384/12 = 32 m/s
Now,
the first train crosses the second train (which has the same length) in 12 seconds while travelling in opposite directions.
The combined length of both trains is:
Total distance = 384 + 384 = 768 meters
Let the speed of the second train = x m/s
The total time taken to cross each other = 12 seconds
so;
Relative speed = Total distance/Time = 768/12 = 64 m/s
Relative speed = Speed of first train + x = 32 + x = 64 m/s
⇒ x = 64 − 32 = 32m/s