Mensa IQ Test Mensa IQ Syllogisms and Logical Arguments 8

Question 1

Premises: All P are Q. Some R are Q. Which conclusion is valid?

Accepted Answer

Nothing necessarily follows about P and R

Answer

P⊂Q and R∩Q≠∅ does not establish any relationship between P and R.

Question 2

Argument: 'Steak has iron, spinach has iron — therefore steak and spinach taste the same.' What is wrong?

Accepted Answer

False analogy — sharing one property doesn't make things identical

Answer

Concluding things are alike in all respects because they share one property is a false analogy.

Question 3

All birds have wings. All creatures with wings can fly. Penguins are birds. Which conclusion follows?

Accepted Answer

Penguins can fly (logically, given these premises)

Answer

Syllogistically valid: Penguin→Bird→Wings→Fly. The premises are factually flawed, but the argument form is valid.

Question 4

Premises: No A are B. Some C are A. Which is valid?

Accepted Answer

Some C are not B

Answer

The C-members that are A cannot be B (since no A is B) → some C are not B.

Question 5

Argument: 'I can't be wrong — I've never been wrong before.' This is which fallacy?

Accepted Answer

Appeal to personal incredulity / overconfidence bias

Answer

Using one's own past record as proof of infallibility is a form of appeal to personal authority / overconfidence fallacy.

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