GCAT Syllogistic Reasoning 2 — Questions and Answers
Question 1: All doctors are scientists. Some scientists are professors. Which conclusion is valid?
- All doctors are professors.
- Some doctors are professors.
- Some scientists are doctors.
- No conclusion can be drawn about doctors and professors. (Correct answer)
Correct answer: No conclusion can be drawn about doctors and professors.
The link between doctors and professors cannot be established because 'some scientists are professors' does not tell us which scientists.
Question 2: No fish are mammals. All whales are mammals. Which conclusion follows?
- Some whales are fish.
- No whales are fish. (Correct answer)
- All mammals are whales.
- Some fish are whales.
Correct answer: No whales are fish.
Since no fish are mammals and all whales are mammals, whales and fish share no members.
Question 3: All A are B. All B are C. No C are D. What can be concluded about A and D?
- All A are D.
- Some A are D.
- No A are D. (Correct answer)
- No conclusion is possible.
Correct answer: No A are D.
A is a subset of B, B is a subset of C, and C excludes D entirely, so A cannot be D.
Question 4: Some managers are leaders. All leaders are communicators. Which must be true?
- All managers are communicators.
- Some managers are communicators. (Correct answer)
- No managers are communicators.
- All communicators are managers.
Correct answer: Some managers are communicators.
The managers who are leaders must also be communicators, so at least some managers are communicators.
Question 5: All poets are dreamers. No dreamer is a banker. Which is valid?
- Some bankers are poets.
- All bankers are dreamers.
- No poet is a banker. (Correct answer)
- Some poets are bankers.
Correct answer: No poet is a banker.
Poets are dreamers and dreamers exclude bankers, so poets and bankers cannot overlap.
Question 6: Some athletes are vegetarians. Some vegetarians are doctors. Which conclusion is valid?
- Some athletes are doctors.
- All athletes are doctors.
- No athletes are doctors.
- No valid conclusion about athletes and doctors. (Correct answer)
Correct answer: No valid conclusion about athletes and doctors.
Two 'some' statements sharing a middle term do not allow any definite conclusion.
Question 7: All red objects are heavy. This ball is not heavy. What follows?
- This ball is red.
- This ball might be red.
- This ball is not red. (Correct answer)
- This ball is sometimes red.
Correct answer: This ball is not red.
By contrapositive: if not heavy, then not red.
GCAT Syllogistic Reasoning 2
All doctors are scientists.
Some scientists are professors.
Which conclusion is valid?