Difficulty: Medium
Correct Answer: 46 min and 12 s
Explanation:
Introduction:
When several runners start together and repeat laps with different lap times, their next common meeting at the start occurs after a time equal to the least common multiple of their lap times.
Given Data / Assumptions:
Concept / Approach:
Compute LCM(252, 308, 198). Convert the resulting seconds to minutes and seconds for a readable time format.
Step-by-Step Solution:
Verification / Alternative check:
Prime factorizations confirm that 2772 is divisible by 252, 308, and 198, and there is no smaller positive time that satisfies all three simultaneously.
Why Other Options Are Wrong:
26 min 18 s, 42 min 36 s, 45 min, and 44 min are not common multiples of all three lap times.
Common Pitfalls:
Taking a simple sum or pairwise LCM instead of the LCM of all three values. Always combine all periods.
Final Answer:
46 min and 12 s
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