Two trains 132 metres and 108 metres in length are running towards eachother on parallel lines, one at the rate of 32 km/hr and another 40 km/hr. Then time taken by the trains in passing each other -
-
15 second
-
12 second
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18 second
-
20 second
B
Correct answer
Explanation
When trains move toward each other, their relative speed is the sum of individual speeds: 32 + 40 = 72 km/hr. Total distance to cover = 132 + 108 = 240 m = 0.24 km. Time = Distance/Speed = 0.24/72 hours = 0.00333 hours. Converting to seconds: 0.00333 × 3600 = 12 seconds. This uses the formula for relative speed when objects move in opposite directions.