Consider the following argument: "Replacing heavy metallic wing brackets with carbon-fiber reinforced polymer (CFRP) brackets on commercial airliners will lead to substantial airline operational savings because lighter aircraft consume significantly less jet fuel per passenger-kilometer." Which of the following is an **UNSTATED ASSUMPTION** required for the conclusion to hold?

(A) The lifecycle manufacturing, inspection, and maintenance costs of CFRP brackets do not exceed the monetary savings gained from reduced fuel consumption

(B) CFRP brackets have an infinite operational lifespan under dynamic cyclical wing loading

(C) Jet fuel prices will increase continuously over the next twenty years

(D) Commercial airline ticket prices will decrease in direct proportion to fuel savings

Answer Key:

Verified in official key

### 1. Strategy & Theoretical Principles In critical reasoning, an assumption is an unstated premise that *must* be true for the argument's conclusion to be logically valid. To verify an assumption, apply the **Negation Test**: if negating the statement shatters the author's conclusion, the statement is a necessary assumption. ### 2. Negation Test Application - **Negate Option A:** "The manufacturing, inspection, and maintenance costs of CFRP brackets *do* exceed the monetary savings gained from fuel consumption." - If this negation is true, the net operational effect is a loss, completely destroying the conclusion that airlines achieve "substantial operational savings". Thus, Option A is a necessary assumption. ### 3. Distractor Forensics - **Option B:** Unnecessarily extreme ("infinite lifespan"). CFRP brackets only need acceptable fatigue life. - **Option C:** Future price increase is not strictly required; savings occur at present fuel prices as long as fuel is consumed. - **Option D:** Ticket prices concern airline revenue, whereas the conclusion specifically concerns airline operational savings. ### 4. Exam Trap & Standard Reference - **Trap Alert:** Look for necessary cost-benefit boundaries when an argument links physical efficiency to financial savings. - **Standard Reference:** GATE General Aptitude Verbal Reasoning.

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