Mensa Mensa IQ Deductive Reasoning Puzzles Questions and Answers 5 — Questions and Answers
Question 1: In a family: Alice is Bob's sister. Bob is Carol's son. Dave is Carol's husband. What is Alice's relationship to Dave?
- Mother
- Aunt
- Daughter (Correct answer)
- Sister
Correct answer: Daughter
Carol is Alice's mother (since Bob is Carol's son and Alice is Bob's sister), and Dave is Carol's husband, making Dave Alice's father and Alice his daughter.
Question 2: The statement 'If it is a square, then it is a rectangle' is true. Which of the following is an equivalent statement?
- If it is a rectangle, then it is a square
- If it is not a rectangle, then it is not a square (Correct answer)
- If it is not a square, then it is not a rectangle
- All rectangles are squares
Correct answer: If it is not a rectangle, then it is not a square
The contrapositive 'If not a rectangle, then not a square' is logically equivalent to the original statement.
Question 3: Six people sit in a row: P, Q, R, S, T, U. P sits next to Q. R sits at one end. T sits next to U but not next to P. S is between R and Q. Which person sits at the other end?
- P
- Q
- T (Correct answer)
- U
Correct answer: T
R is at one end, S is next to R, Q is next to S, P is next to Q, and T-U fill the remaining two seats with T at the far end.
Question 4: What number should replace the question mark? 3, 9, 27, 81, ?
- 162
- 243 (Correct answer)
- 324
- 729
Correct answer: 243
Each term is multiplied by 3, so 81 × 3 = 243.
Question 5: No reptiles are warm-blooded. All snakes are reptiles. Therefore:
- All warm-blooded animals are snakes
- No snakes are warm-blooded (Correct answer)
- Some snakes are warm-blooded
- Reptiles can sometimes be warm-blooded
Correct answer: No snakes are warm-blooded
Since all snakes are reptiles and no reptiles are warm-blooded, no snakes can be warm-blooded.
Question 6: A man walks 3 miles north, 4 miles east, and then heads directly back to his starting point. How far does he walk on the return trip?
- 7 miles
- 5 miles (Correct answer)
- 6 miles
- 4 miles
Correct answer: 5 miles
The north and east legs form a right triangle; the hypotenuse is √(3²+4²) = √25 = 5 miles.
Question 7: All fast runners win medals. Mike did not win a medal. What can we deduce about Mike?
- Mike is a fast runner
- Mike is not a fast runner (Correct answer)
- Mike did not compete
- Mike might be a fast runner
Correct answer: Mike is not a fast runner
By modus tollens: if fast runner → medal, and Mike has no medal, then Mike is not a fast runner.
Mensa Mensa IQ Deductive Reasoning Puzzles Questions and Answers 5
In a family: Alice is Bob's sister.
Bob is Carol's son.
Dave is Carol's husband.
What is Alice's relationship to Dave?