Mensa IQ Test Mensa IQ Syllogisms and Logical Arguments 2

Question 1

All squares are rectangles. All rectangles are parallelograms. Which conclusion is VALID?

Accepted Answer

All squares are parallelograms

Answer

Barbara (AAA-1): All S→R, All R→P, therefore All S→P.

Question 2

Some birds cannot fly. All penguins are birds. Which conclusion is DEFINITELY valid?

Accepted Answer

All penguins are birds

Answer

The only statement that necessarily follows from the given premises is the second premise itself: all penguins are birds.

Question 3

No vegetarians eat meat. Jane is a vegetarian. Therefore:

Accepted Answer

Jane does not eat meat

Answer

Jane ∈ vegetarians, and no vegetarian eats meat → Jane does not eat meat.

Question 4

All politicians are public speakers. Some liars are politicians. Which conclusion follows?

Accepted Answer

Some liars are public speakers

Answer

The liar-politicians are public speakers (all politicians are public speakers) → some liars are public speakers.

Question 5

Premise 1: If it rains, the ground gets wet. Premise 2: The ground is wet. What can we conclude?

Accepted Answer

It may or may not have rained

Answer

Affirming the consequent is a fallacy — wet ground could have other causes; we cannot conclude it rained.

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