Free Mensa IQ Critical Thinking Practice Test

Question 1

All roses are flowers. Some flowers fade quickly. Therefore:

Accepted Answer

B. Some roses may fade quickly

Answer

This is a syllogism. We know all roses are flowers, and some flowers fade quickly. It's possible (but not certain) that some of those fading flowers are roses. We cannot conclude all roses fade quickly, only that some roses may.

Question 2

If it is true that 'No X is Y' and 'All Z is X', which must be true?

Accepted Answer

B. No Z is Y

Answer

If no X is Y, and all Z is X, then Z is a subset of X. Since nothing in X is Y, nothing in Z (being part of X) can be Y. Therefore 'No Z is Y' must be true.

Question 3

A study shows students who eat breakfast score higher on tests. A teacher concludes breakfast causes better test scores. What flaw exists in this reasoning?

Accepted Answer

B. Correlation does not imply causation

Answer

The classic logical flaw: correlation does not imply causation. Students who eat breakfast may also have other habits (better sleep, stable home environment) that cause higher scores. The relationship is correlational, not necessarily causal.

Question 4

Five people sit in a row. Anna is not at either end. Ben is to the right of Anna. Clara is at the leftmost seat. Dana is between Clara and Anna. Who is at the rightmost seat?

Accepted Answer

C. Eric

Answer

Clara is at position 1 (leftmost). Dana is between Clara and Anna. So the order so far: Clara(1), Dana(2), Anna(3). Ben is to the right of Anna, so Ben is at 4 or 5. Eric takes the remaining spot. Since Anna is not at an end and Ben must be right of Anna, Ben is at 4 and Eric is at 5 (rightmost).

Question 5

Which argument contains circular reasoning?

Accepted Answer

B. This book is trustworthy because the author says it is accurate

Answer

Circular reasoning (begging the question) occurs when the conclusion is used as a premise. 'The book is trustworthy because the author says it is accurate' uses the author's credibility as proof of the author's credibility — the conclusion supports itself.

Mensa Practice Test Practice Test

Mensa Practice Test Practice Test

Free Mensa IQ Critical Thinking Practice Test