Basic Ability Test Basic Ability Logical Deduction and Syllogisms 5 — Questions and Answers
Question 1: All mammals breathe air. Dolphins breathe air. What can be concluded?
- Dolphins are mammals
- Dolphins may or may not be mammals (Correct answer)
- Dolphins are not mammals
- All air-breathers are mammals
Correct answer: Dolphins may or may not be mammals
Breathing air is necessary for mammals but not exclusive to them, so dolphins' status cannot be determined from this alone.
Question 2: Some doctors are researchers. Some researchers publish papers. What must be true?
- Some doctors publish papers
- No doctors publish papers
- All researchers publish papers
- Nothing certain about doctors and papers (Correct answer)
Correct answer: Nothing certain about doctors and papers
Two partial overlaps do not guarantee a third overlap between the first and last category.
Question 3: If the switch is off, the light is off. The light is on. What follows?
- The switch is off
- The switch is on (Correct answer)
- The light might still be off
- Nothing can be concluded
Correct answer: The switch is on
By contrapositive, if the light is on (not off), the switch must be on (not off).
Question 4: All novels are books. Some books are rare. Which conclusion must hold?
- All novels are rare
- Some novels are rare
- No novels are rare
- Nothing definite about novels and rarity (Correct answer)
Correct answer: Nothing definite about novels and rarity
The rare books may be entirely outside the set of novels, so nothing definite can be concluded.
Question 5: Every prime number greater than 2 is odd. 17 is a prime number greater than 2. What follows?
- 17 is even
- 17 is odd (Correct answer)
- 17 is not prime
- Odd numbers are prime
Correct answer: 17 is odd
17 satisfies the condition, so by modus ponens it must be odd.
Question 6: No contract is valid without a signature. This contract is valid. What follows?
- This contract has no signature
- This contract has a signature (Correct answer)
- Signatures make all contracts valid
- Nothing can be determined
Correct answer: This contract has a signature
By contrapositive, a valid contract must have a signature.
Question 7: All leaders inspire others. Some managers are leaders. Which statement is certain?
- All managers inspire others
- Some managers inspire others (Correct answer)
- No managers inspire others
- All who inspire are managers
Correct answer: Some managers inspire others
The managers who are leaders must inspire others, so at least some managers do.
Basic Ability Test Basic Ability Logical Deduction and Syllogisms 5
All mammals breathe air.
Dolphins breathe air.
What can be concluded?