Difficulty: Easy
Correct Answer: 48 days
Explanation:
Introduction / Context:
This is a standard rate extraction problem: use individual times for A and B and the joint time for all three to isolate the third individual rate.
Given Data / Assumptions:
Concept / Approach:
Sum A and B rates, subtract from the combined rate to get C’s rate, then invert to get C’s time.
Step-by-Step Solution:
Verification / Alternative check:
Check: 1/24 + 1/16 + 1/48 = 2/48 + 3/48 + 1/48 = 6/48 = 1/8, consistent with the given joint time.
Why Other Options Are Wrong:
32, 36, 40, 24 do not match the extracted rate from the combined data and lead to incorrect total rates when recombined.
Common Pitfalls:
Arithmetic mistakes with denominators 24, 16, and 8; forgetting to subtract A + B from the total rather than averaging times.
Final Answer:
48 days
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