LNAT Logical Deduction 5 — Questions and Answers
Question 1: Argument: 'My client could not have committed the robbery at 9 pm because he was dining with me at 9 pm.' This is an example of:
- Tu quoque
- Alibi / rebuttal evidence (Correct answer)
- Ad hominem
- Appeal to authority
Correct answer: Alibi / rebuttal evidence
Providing a location alibi is a direct rebuttal that undermines the prosecution's claim by showing a contradictory fact.
Question 2: All statutory instruments must be laid before Parliament. This regulation was not laid before Parliament. Therefore:
- The regulation is still valid
- The regulation is not a statutory instrument (Correct answer)
- The regulation was passed by emergency powers
- Parliament approved it implicitly
Correct answer: The regulation is not a statutory instrument
By contrapositive: if not laid before Parliament, then not a statutory instrument.
Question 3: Passage: 'Raising the minimum wage always increases unemployment.' Which finding most strengthens this?
- A country raised minimum wage and unemployment fell
- Several countries raised minimum wage and saw no change in unemployment
- A meta-analysis shows unemployment rises in 80% of cases after minimum wage increases (Correct answer)
- Employers prefer lower wages
Correct answer: A meta-analysis shows unemployment rises in 80% of cases after minimum wage increases
Empirical evidence showing unemployment rises in a majority of observed cases directly supports the causal claim.
Question 4: P: If the appeal succeeds, the sentence is reduced. Q: If the sentence is reduced, the defendant is released early. R: The appeal did not succeed. What follows?
- The defendant is released early
- The sentence is not reduced
- The defendant serves the full sentence
- Nothing follows about the sentence (Correct answer)
Correct answer: Nothing follows about the sentence
The conditionals only tell us what happens if the appeal succeeds; since it failed, the conditionals are not triggered and nothing can be deduced.
Question 5: In a survey, 60% of respondents support capital punishment, yet juries rarely recommend it. Which best explains this paradox?
- The survey sample was biased toward supporters
- Jurors apply a higher standard of proof than abstract opinion allows (Correct answer)
- Capital punishment is illegal
- Juries are unrepresentative of the public
Correct answer: Jurors apply a higher standard of proof than abstract opinion allows
The act of deciding a real case imposes a higher evidential burden than expressing an abstract preference, explaining the gap.
Question 6: Some precedents are overruled. All overruled precedents lose binding force. No persuasive authorities have binding force. Which is a valid conclusion?
- Some precedents lose binding force (Correct answer)
- All precedents lose binding force
- Persuasive authorities are overruled precedents
- No precedents have binding force
Correct answer: Some precedents lose binding force
Some precedents are overruled, and all overruled precedents lose binding force, so some precedents lose binding force.
Question 7: A logician says: 'This statement is false.' If the statement is true, it is false; if it is false, it is true. This is an example of:
- A valid syllogism
- The liar's paradox — a self-referential contradiction (Correct answer)
- Circular reasoning
- A false dilemma
Correct answer: The liar's paradox — a self-referential contradiction
The liar's paradox arises when a statement refers to its own truth value, producing an irresolvable contradiction.
LNAT Logical Deduction 5
Argument: 'My client could not have committed the robbery at 9 pm because he was dining with me at 9 pm.' This is an example of: