Difficulty: Medium
Correct Answer: Cannot be determined
Explanation:
Introduction / Context:
We are given two overlapping three-person averages that share T. The question asks for the five-person average of P, T, R, F, and G. We need the sum of these five, but T appears in both triples and is unknown individually.
Given Data / Assumptions:
Concept / Approach:
Sum of five S = (P + T + R) + (T + F + G) − T = 163/3 + 159 − T. Because T is unknown, S cannot be uniquely determined; many values of T satisfy the given equations with different S.
Step-by-Step Explanation:
Compute (P + T + R) = 163/3Compute (T + F + G) = 159S = 163/3 + 159 − T (depends on T)
Verification / Alternative check:
Pick two different T values that keep both equations valid (by adjusting P + R and F + G accordingly); S changes with T, proving non-uniqueness.
Why Other Options Are Wrong:
Any specific numeric average (e.g., 53.8, 52.4, 53.4, 54.0) implies a fixed S, which we cannot infer uniquely without T.
Common Pitfalls:
Assuming the shared member’s weight cancels out. It does not because it appears once positively after correcting for double counting.
Final Answer:
Cannot be determined
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