Correct Answer: 12
Explanation:
Step 1: Understand the given data
Step 2: Calculate the speed of each train
Speed = Distance / Time
Speed of Train A = 120 / 10 = 12 m/s Speed of Train B = 120 / 15 = 8 m/s
Step 3: Find the relative speed
Since the trains are moving in opposite directions, their relative speeds will be added:
Relative speed = 12 + 8 = 20 m/s
Step 4: Total distance to be covered when trains cross each other
Each train is 120 m long, so total distance = 120 + 120 = 240 meters
Step 5: Calculate the time to cross each other
Time = Total Distance / Relative Speed = 240 / 20 = 12 seconds
Answer: 12 seconds
The two trains will cross each other in 12 seconds when moving in opposite directions.
This question demonstrates how the concept of relative speed applies when two moving bodies travel toward each other. It’s a commonly tested topic in time-speed-distance problems found in competitive exams.
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