PrepTest 143, Section 4, Question 11
A development company has proposed building an airport(55 more words not shown)
The reasoning in the argument(6 more words not shown)
- Atreats a sufficient(10 more words not shown)
- Bconcludes that something(11 more words not shown)
- Cconcludes, on the(15 more words not shown)
- Dfails to consider(10 more words not shown)
- Eoverlooks the possibility(9 more words not shown)
Reading the argument
What if the airport gets built whether the residents like it or not?
We're told that majority support guarantees construction. That gives us one route to getting the airport. It doesn't tell us that the development company must abandon the project without that support. Imagine a wealthy backer who intends to finance the project regardless of public opinion. Nothing we've read rules that possibility out.
What we’re looking for
Now accept the prediction that most residents probably won't favor the proposal. The author still hasn't shown why that makes construction unlikely. Perhaps the residents' approval isn't required. For the flaw, I want the answer describing this confusion: treating one way to ensure construction as the only way construction can happen.
Working the answers
- ACorrect
A sufficient condition is enough to produce the result. Here, majority support would be enough to get the airport built. A necessary condition is something the result requires. The argument treats majority support as though construction requires it, even though the stated rule only says support would ensure construction.
That's why the unfavorable public opinion doesn't settle the forecast. If another route to construction is available, the airport could still be likely to get built.
- B
The residents believe the airport would create noise problems, but the argument doesn't use their belief to prove that noise problems will occur. It uses that belief to predict their opposition. And the final conclusion is about what is unlikely, not what must be true. B doesn't describe the actual inference.
- C
The conclusion remains qualified: construction is unlikely. The author doesn't turn a low probability into certainty that the airport won't be built. The error is moving from unlikely support to unlikely construction, not changing “unlikely” into “impossible.”
- D
The views of people outside Dalton might matter in some real decision, but we haven't been given a rule about those views. Even setting them aside, we can see the problem: the rule about Dalton residents doesn't make their approval a requirement for construction.
- E
Economic benefits might give residents a reason to support the proposal despite noise concerns. But the central mistake survives even if we grant that the majority probably won't support it. Without knowing that majority support is required, we still can't conclude construction is unlikely.
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