Mensa IQ Test Mensa IQ Deductive Reasoning Puzzles Questions and Answers 2 — Questions and Answers
Question 1: All doctors are professionals. No criminals are professionals. Therefore:
- Some doctors are criminals
- No doctors are criminals (Correct answer)
- Some criminals are doctors
- All professionals are doctors
Correct answer: No doctors are criminals
All doctors are professionals; no criminals are professionals — therefore no doctors can be criminals.
Doctors ⊆ Professionals, Criminals ∩ Professionals = ∅. Since doctors are all in the 'professionals' set and criminals have no overlap with professionals, doctors and criminals have no overlap. Therefore: No doctors are criminals.
Question 2: If it is raining, I carry an umbrella. I am carrying an umbrella. Therefore:
- It must be raining
- It might or might not be raining (Correct answer)
- It is definitely not raining
- It is sunny
Correct answer: It might or might not be raining
Carrying an umbrella doesn't prove it's raining — you may carry it for other reasons. This is the logical fallacy of affirming the consequent.
The statement is: If rain → umbrella. Having an umbrella does NOT guarantee rain (affirming the consequent fallacy). You could carry an umbrella when it's sunny, just in case. So it might or might not be raining.
Question 3: In a village, the barber shaves all those, and only those, who do not shave themselves. Who shaves the barber?
- The barber shaves himself
- Someone else shaves the barber
- The barber cannot logically exist (Correct answer)
- The mayor shaves the barber
Correct answer: The barber cannot logically exist
This is Russell's Paradox — if the barber shaves himself, he shouldn't; if he doesn't, he must. The barber cannot logically exist.
Russell's Barber Paradox. Case 1: Barber shaves himself → contradicts the rule (he only shaves those who don't shave themselves). Case 2: Barber doesn't shave himself → contradicts the rule (he must shave all who don't shave themselves). Both cases lead to contradiction — the barber cannot logically exist.
Question 4: Four cards show: 3, 8, RED, BLUE. Rule: 'If a card has an even number, the other side is red.' Which cards must you turn over to test the rule?
- 3 and RED
- 8 and BLUE (Correct answer)
- 8 and RED
- 3 and BLUE
Correct answer: 8 and BLUE
You must check: 8 (to see if it's red) and BLUE (to ensure it doesn't hide an even number). This is the Wason selection task.
Rule: even number → red. Check '8': if the back isn't red, the rule is violated. Check 'BLUE': if it has an even number, the rule is violated (even must be red, not blue). Card '3' is odd — rule doesn't apply. Card 'RED' can have any number — the rule only restricts even numbers.
Question 5: Three boxes are labeled 'APPLES', 'ORANGES', and 'MIXED'. All labels are wrong. You draw from the 'MIXED' box and get an apple. What does the 'APPLES' box contain?
- Apples
- Oranges (Correct answer)
- Mixed fruit
- Cannot be determined
Correct answer: Oranges
The 'MIXED' box is actually APPLES. The 'APPLES' box can't have apples, so it must have ORANGES.
The 'MIXED' box can't be mixed (all labels wrong), and you drew an apple, so it's APPLES only. The 'APPLES' box can't have apples (label is wrong), and apples are taken — so it has ORANGES. The 'ORANGES' box must have the mixed fruit.
Question 6: Some artists are teachers. All teachers are creative. Therefore:
- All artists are creative
- Some artists are creative (Correct answer)
- No artists are creative
- All creative people are artists
Correct answer: Some artists are creative
Artists who are teachers are creative (all teachers are creative). But not all artists are teachers, so only SOME artists are guaranteed to be creative.
Some artists are teachers (overlap exists). All teachers are creative. Therefore, the artists who are teachers are creative. Since only SOME artists are teachers, only SOME artists are guaranteed to be creative. We cannot say ALL artists are creative.
Mensa IQ Test Mensa IQ Deductive Reasoning Puzzles Questions and Answers 2
All doctors are professionals.
No criminals are professionals.
Therefore: