GMA Syllogisms 2 — Questions and Answers
Question 1: All doctors are professionals. Some professionals are wealthy. Which conclusion is valid? (A) All doctors are wealthy. (B) Some doctors may be wealthy. (C) No doctors are wealthy. (D) All wealthy people are doctors.
- All doctors are wealthy.
- Some doctors may be wealthy. (Correct answer)
- No doctors are wealthy.
- All wealthy people are doctors.
Correct answer: Some doctors may be wealthy.
Since all doctors are professionals, and some professionals are wealthy, it is possible (but not certain) that some doctors are among the wealthy professionals. We can only conclude 'some doctors may be wealthy'.
Syllogistic reasoning requires careful attention to quantifiers (all, some, no). 'All doctors are professionals' places doctors fully within professionals. 'Some professionals are wealthy' means the wealthy subset overlaps with professionals but not necessarily with doctors specifically. We cannot conclude all doctors are wealthy — only that it's possible some are. Invalid reasoning would over-generalise the 'some' statement.
Question 2: No birds are mammals. All penguins are birds. Which conclusion must be true? (A) Some penguins are mammals. (B) All mammals are birds. (C) No penguins are mammals. (D) Some birds are penguins.
- Some penguins are mammals.
- All mammals are birds.
- No penguins are mammals. (Correct answer)
- Some birds are penguins.
Correct answer: No penguins are mammals.
Since all penguins are birds, and no birds are mammals, it follows logically that no penguins can be mammals.
Syllogism: P1: No birds are mammals (birds ∩ mammals = ∅). P2: All penguins are birds (penguins ⊆ birds). Therefore: penguins ⊆ birds and birds ∩ mammals = ∅, so penguins ∩ mammals = ∅. Conclusion C ('No penguins are mammals') follows necessarily. Option D ('Some birds are penguins') is true but is given in P2, not a new logical inference.
Question 3: All roses are flowers. All flowers need water. Which conclusion is valid? (A) Only roses need water. (B) Some water-needing things are not flowers. (C) All roses need water. (D) All water-needing things are roses.
- Only roses need water.
- Some water-needing things are not flowers.
- All roses need water. (Correct answer)
- All water-needing things are roses.
Correct answer: All roses need water.
Since all roses are flowers, and all flowers need water, it logically follows that all roses need water (transitive relationship).
This is a categorical syllogism using the transitive property of universal inclusion. All roses ⊆ flowers, and all flowers ⊆ water-needing things. Therefore, all roses ⊆ water-needing things. Conclusion C is the valid transitive inference. Options A and D make unwarranted exclusive claims, and Option B, while possibly true, is not supported by the given premises.
Question 4: Some athletes are vegetarians. All vegetarians avoid meat. Which conclusion is valid? (A) All athletes avoid meat. (B) No athletes avoid meat. (C) Some athletes avoid meat. (D) All meat-avoiders are athletes.
- All athletes avoid meat.
- No athletes avoid meat.
- Some athletes avoid meat. (Correct answer)
- All meat-avoiders are athletes.
Correct answer: Some athletes avoid meat.
Since some athletes are vegetarians, and all vegetarians avoid meat, those particular athletes (the vegetarian ones) also avoid meat. Therefore 'some athletes avoid meat'.
Premises: Some athletes ∈ vegetarians; All vegetarians avoid meat. The vegetarian athletes are a subset of both athletes and vegetarians, so they also avoid meat. We can conclude that some (not all) athletes avoid meat. 'All athletes avoid meat' would require all athletes to be vegetarians, which is not stated.
Question 5: No fish can survive on land. Sharks are fish. Which conclusion necessarily follows? (A) Sharks can survive on land. (B) Sharks cannot survive on land. (C) Some fish can survive on land. (D) No sharks are fish.
- Sharks can survive on land.
- Sharks cannot survive on land. (Correct answer)
- Some fish can survive on land.
- No sharks are fish.
Correct answer: Sharks cannot survive on land.
Since no fish can survive on land, and sharks are fish, sharks fall into the category of fish that cannot survive on land.
Syllogism: P1: No fish survive on land (fish ∩ land-survivors = ∅). P2: All sharks are fish (sharks ⊆ fish). Conclusion: Sharks ⊆ fish, and fish ∩ land-survivors = ∅, therefore sharks ∩ land-survivors = ∅ — sharks cannot survive on land. This is a valid universal syllogism (Barbara form in negative).
Question 6: All managers have authority. Some employees are managers. Which conclusion is valid? (A) All employees have authority. (B) No employees have authority. (C) Some employees have authority. (D) All authority figures are employees.
- All employees have authority.
- No employees have authority.
- Some employees have authority. (Correct answer)
- All authority figures are employees.
Correct answer: Some employees have authority.
Since some employees are managers, and all managers have authority, those employees who are managers also have authority. Therefore, some employees have authority.
Premises: All managers ⊆ authority-holders; Some employees ∈ managers. The managerial employees are a subset of both employees and managers, so they also have authority. We conclude some employees have authority. 'All employees have authority' would require all employees to be managers. Options A, B, and D are not supported by the given premises.
GMA Syllogisms 2
All doctors are professionals.
Some professionals are wealthy.
Which conclusion is valid?
(A) All doctors are wealthy.
(B) Some doctors may be wealthy.
(C) No doctors are wealthy.
(D) All wealthy people are doctors.