Mensa IQ Test Mensa IQ Syllogisms and Logical Arguments 4 — Questions and Answers
Question 1: All writers are readers. No readers are illiterate. Therefore:
- No writers are illiterate (Correct answer)
- Some writers are illiterate
- All illiterate people are writers
- Some readers are writers
Correct answer: No writers are illiterate
All W→R and No R→I (Celarent) → No W→I.
Question 2: Argument: 'You should agree with me because everyone in our town does.' This is which fallacy?
- Ad populum (appeal to the crowd) (Correct answer)
- Ad hominem
- Straw man
- False dilemma
Correct answer: Ad populum (appeal to the crowd)
Appealing to popular opinion as proof of truth is the ad populum fallacy.
Question 3: Premise: If P then Q. Premise: P is true. What can we conclude?
- Q is true (Correct answer)
- P is false
- Q is false
- Nothing can be concluded
Correct answer: Q is true
Modus ponens: P→Q; P → Q.
Question 4: No herbivores eat meat. Cows are herbivores. Zebras are herbivores. Which MUST be true?
- Neither cows nor zebras eat meat (Correct answer)
- Cows eat meat
- Zebras eat meat
- Some herbivores eat meat
Correct answer: Neither cows nor zebras eat meat
Both are herbivores, and no herbivore eats meat → neither cows nor zebras eat meat.
Question 5: 'Since we allow people to drive at 16, we should allow them to vote at 16.' This argument uses:
- Argument from analogy (Correct answer)
- Ad hominem
- Slippery slope
- Circular reasoning
Correct answer: Argument from analogy
It draws a parallel between two activities at the same age — an argument by analogy.
Question 6: All A are B. All B are C. No C are D. Which conclusion is valid?
- No A are D (Correct answer)
- Some A are D
- All D are A
- Some C are A
Correct answer: No A are D
A→B→C and No C→D → No A→D (extended Barbara + Celarent chain).
Question 7: Argument: 'You're wrong about climate change — you're not even a scientist.' This is which fallacy?
- Ad hominem (attacking the person) (Correct answer)
- Straw man
- False cause
- Appeal to authority
Correct answer: Ad hominem (attacking the person)
Dismissing an argument by attacking the arguer's credentials rather than the argument is ad hominem.
Mensa IQ Test Mensa IQ Syllogisms and Logical Arguments 4
All writers are readers.
No readers are illiterate.
Therefore: