Difficulty: Easy
Correct Answer: 6 seconds
Explanation:
Introduction / Context:
When two objects move in opposite directions, their relative speed is the sum of their individual speeds. Passing a person requires covering only the train’s length at the relative speed.
Given Data / Assumptions:
Concept / Approach:
Relative speed v_rel = (60 + 6) km/h = 66 km/h. Convert v_rel to m/s; time t = L / v_rel_mps.
Step-by-Step Solution:
Verification / Alternative check:
If the man were stationary, time would be 110/(60*5/18) ≈ 6.6 s; walking toward the train reduces time to 6 s—consistent.
Why Other Options Are Wrong:
7⅓ s and 6⅔ s correspond to incorrect relative speeds; “Data inadequate” is incorrect because all needed values are given.
Common Pitfalls:
Subtracting speeds instead of adding for opposite directions; using platform distance instead of train length.
Final Answer:
6 seconds
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