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PT9 S4 Q04

Natalie.endenburgNatalie.endenburg Monthly Member

Lately I have been having a lot of trouble with "must be true" questions. Can anyone explain why C was the correct answer choice for this question, and not D?

Thank you!


  • Law and YodaLaw and Yoda Alum Member
    edited May 2020 4199 karma

    This looks like valid argument 1

    If A then B
    If not B then not A

    The passage is saying this essentially:

    DF (Democracy functions well) -> Moral + Intelligent

    Moral or Intelligent -> DF (this is the contrapositive)

    C is the Contrapositive of the original statement and is thus the correct answer.
    D is is a Mistaken Negation of the original statement because it negates the sufficient and necessary conditions without reversing them.

  • dazedandconfused-1dazedandconfused-1 Alum Member
    258 karma

    If we translate the question stem to a set of conditionals, it will look like:
    "if a democracy functions well, then the electorate is moral and intelligent." or
    DFW --> M and I.

    The contrapositive of this is (using DeMorgan's Law) : not M or not I --> not DFW.

    C states the contrapositive: "If the electorate is not moral or not intelligent, then a democracy will not function well. D says not DFW --> not M or not I, which is a mistaken reversal.

    Hope this helps!

  • Natalie.endenburgNatalie.endenburg Monthly Member
    7 karma

    Thank you very much to both of you for your help! :)

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