Difficulty: Medium
Correct Answer: 800 km
Explanation:
Introduction / Context:
Splitting a journey into equal halves by distance but different speeds requires summing the two leg times and equating to the given total time to solve for the half-distance.
Given Data / Assumptions:
Concept / Approach:
Total time = x/60 + x/50. Solve for x, then total distance = 2x.
Step-by-Step Solution:
Verification / Alternative check:
Time check: 400/60 = 6.666... h; 400/50 = 8 h; sum = 14.666... h as given.
Why Other Options Are Wrong:
They result from arithmetic slips or misinterpreting “half the distance” vs. “half the time.”
Common Pitfalls:
Confusing equal halves by distance with equal halves by time; forgetting to convert minutes to fractional hours.
Final Answer:
800 km
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