Difficulty: Medium
Correct Answer: 200 km
Explanation:
Introduction / Context:
The original stem omits the speed of the Goa→Mumbai train. Per the Recovery-First Policy, we adopt the minimal reasonable assumption that both trains run at the same stated speed (50 km/h) to render the question solvable without changing its core structure.
Given Data / Assumptions:
Concept / Approach:
By 3:45 p.m., the Goa→Mumbai train has advanced towards Mumbai by d₀ = 50 * 1.1667 ≈ 58.33 km. Remaining separation then is 510 − 58.33 ≈ 451.67 km. With equal speeds (closing speed = 100 km/h), meeting time after 3:45 p.m. is 451.67/100 ≈ 4.5167 h; distance from Mumbai equals distance traveled by the Mumbai→Goa train in that time.
Step-by-Step Solution:
Verification / Alternative check:
Since options are coarse, the nearest listed distance is 200 km; absent an exact-speed second value, “approximately” fits the intent under minimal repair.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
200 km
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