Free Syllogisms MCQs with Answers

11. Statements: All A are B. No B are C. Conclusion: Some C are A. This conclusion is

• A. valid
• B. invalid
• C. always true
• D. possibly true

Explanation: A is inside B, and B is entirely separate from C, so no A can be C at all, which makes the proposed conclusion the exact opposite of what follows. Using letters rather than familiar words removes the temptation to reason from world knowledge. The valid conclusion here is that no A is C.

12. Statements: All squares are quadrilaterals. Some quadrilaterals are not squares. Conclusion: Some quadrilaterals are squares. This conclusion is

• A. valid
• B. invalid
• C. contradictory
• D. irrelevant

Explanation: If all squares are quadrilaterals and squares exist, then some quadrilaterals must be squares, which is a valid conversion of a universal affirmative into a particular one. The second premise adds that not every quadrilateral is a square, which is consistent rather than contradictory. Both statements can be true at once.

13. Statements: Only graduates can apply. Sana applied successfully. Which conclusion follows?

• A. Sana is a graduate
• B. Sana is not a graduate
• C. All graduates applied
• D. Nothing follows

Explanation: The word only makes graduation a necessary condition for applying, so a successful applicant must be a graduate. It does not follow that every graduate applied, which would be the converse. Only statements are read as if not a graduate, then cannot apply.

14. Statements: Some birds are parrots. All parrots are green. Which conclusion follows?

• A. Some birds are green
• B. All birds are green
• C. No bird is green
• D. All green things are birds

Explanation: The birds that are parrots must be green, so some birds are certainly green, while the other birds could be any colour. A conclusion cannot be broader than the narrowest premise supporting it. The last option reverses a universal, which is never valid.

15. Statements: All liquids are fluids. Some fluids are gases. Conclusion: Some liquids are gases. This conclusion is

• A. valid
• B. invalid
• C. necessarily true
• D. self evident

Explanation: The gases among fluids need not overlap with the liquids at all, and in reality they do not, so the conclusion does not follow from the premises. This has the same faulty structure as the earlier engineers and unemployed question. Real world knowledge here happens to agree with the logic, but the logic alone settles it.

16. In syllogistic reasoning, a conclusion containing the word all can follow only if

• A. at least one premise is particular
• B. both premises are universal
• C. one premise is negative
• D. both premises are negative

Explanation: A universal conclusion requires universal support, so any particular premise limits the conclusion to some. Two negative premises yield no conclusion at all, which disposes of the last option. These structural rules let many questions be answered without examining the content.

17. Statements: No politician is honest. Some honest people are rich. Which conclusion follows?

• A. Some rich people are not politicians
• B. No rich person is a politician
• C. All rich people are honest
• D. Some politicians are rich

Explanation: The rich people who are honest cannot be politicians, so at least some rich people fall outside the politician group. The stronger universal claim is not supported, since other rich people may well be politicians. This is the same structure as the earlier drivers question.

18. Two negative premises, such as "No A is B" and "No B is C", yield

• A. the conclusion that no A is C
• B. the conclusion that all A are C
• C. no valid conclusion
• D. the conclusion that some A are C

Explanation: Nothing links A and C when both premises merely exclude, so A and C might overlap completely, partly or not at all. This is one of the standard rules of the syllogism: from two negatives nothing follows. It is a common trap because the pattern looks like a chain.

19. Statements: All medicines are drugs. No drug is a food. Which conclusion follows?

• A. Some medicines are foods
• B. No medicine is a food
• C. All foods are drugs
• D. Some drugs are medicines only

Explanation: Medicines lie inside drugs, and drugs are wholly excluded from foods, so medicines are excluded as well. The exclusion inherited by a subset is the key move in every syllogism of this shape. The third option illegitimately reverses a negative premise.

20. Statements: Some students are hardworking. All hardworking people succeed. Conclusion: All students succeed. This conclusion is

• A. valid
• B. invalid
• C. necessarily true
• D. identical to the premise

Explanation: Only the hardworking students are guaranteed success, so the valid conclusion is that some students succeed, not all. Widening a some premise into an all conclusion is the single most common error in this topic. Always check that the quantity of the conclusion matches its support.