Reasoning — Syllogism

9 mins
Time
11
Questions
🎓
1
Per Q

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Reasoning — Syllogism — Questions with Answers Open after you finish the quiz — all 11 questions, with answers and explanations.
Q1. Statements: 1. All pens are pencils. 2. All pencils are erasers. Conclusions: I. All pens are erasers. II. Some erasers are pens.
  1. Only conclusion I follows.
  2. Only conclusion II follows.
  3. Both conclusions I and II follow.
  4. Neither conclusion I nor II follows.
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Answer: C. Both conclusions I and II follow.
From statement 1 (All pens are pencils) and statement 2 (All pencils are erasers), we can logically deduce that 'All pens are erasers'. Thus, Conclusion I follows. If 'All pens are erasers', it directly implies that 'Some erasers are pens'. Thus, Conclusion II also follows. Therefore, both conclusions I and II follow.
Q2. Statements: 1. Some books are papers. 2. No paper is a pen. Conclusions: I. Some books are not pens. II. No pen is a paper.
  1. Only conclusion I follows.
  2. Only conclusion II follows.
  3. Both conclusions I and II follow.
  4. Neither conclusion I nor II follows.
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Answer: C. Both conclusions I and II follow.
From statement 1 (Some books are papers) and statement 2 (No paper is a pen), it implies that the 'some' part of books that are papers cannot be pens. So, 'Some books are not pens'. Thus, Conclusion I follows. From statement 2 (No paper is a pen), it directly implies 'No pen is a paper'. Thus, Conclusion II also follows. Therefore, both conclusions I and II follow.
Q3. Statements: 1. All chairs are tables. 2. Some tables are desks. Conclusions: I. Some chairs are desks. II. Some desks are tables.
  1. Only conclusion I follows.
  2. Only conclusion II follows.
  3. Both conclusions I and II follow.
  4. Neither conclusion I nor II follows.
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Answer: B. Only conclusion II follows.
From statement 1 (All chairs are tables) and statement 2 (Some tables are desks), there is no definite direct or indirect connection established between 'chairs' and 'desks'. So, Conclusion I (Some chairs are desks) does not follow. From statement 2 (Some tables are desks), it directly implies 'Some desks are tables'. Thus, Conclusion II follows. Therefore, only conclusion II follows.
Q4. Statements: 1. All fruits are vegetables. 2. No vegetable is a root. Conclusions: I. No fruit is a root. II. Some vegetables are not roots.
  1. Only conclusion I follows.
  2. Only conclusion II follows.
  3. Both conclusions I and II follow.
  4. Neither conclusion I nor II follows.
Show answer
Answer: C. Both conclusions I and II follow.
From statement 1 (All fruits are vegetables) and statement 2 (No vegetable is a root), since all fruits are part of vegetables, and no vegetable is a root, it logically follows that 'No fruit is a root'. Thus, Conclusion I follows. From statement 2 (No vegetable is a root), it directly implies that all vegetables are not roots, which means 'Some vegetables are not roots'. Thus, Conclusion II also follows. Therefore, both conclusions I and II follow.
Q5. Statements: 1. Some cars are bikes. 2. All bikes are cycles. 3. Some cycles are trucks. Conclusions: I. Some cars are cycles. II. Some bikes are trucks. III. Some trucks are cycles.
  1. Only I and II follow.
  2. Only I and III follow.
  3. Only II and III follow.
  4. All I, II and III follow.
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Answer: B. Only I and III follow.
From statement 1 (Some cars are bikes) and statement 2 (All bikes are cycles), we can deduce that 'Some cars are cycles'. Thus, Conclusion I follows. From statement 2 (All bikes are cycles) and statement 3 (Some cycles are trucks), there is no definite connection established between 'bikes' and 'trucks'. So, Conclusion II (Some bikes are trucks) does not follow. From statement 3 (Some cycles are trucks), it directly implies 'Some trucks are cycles'. Thus, Conclusion III follows. Therefore, only conclusions I and III follow.
Q6. Statements: 1. All A are B. 2. Some B are C. Conclusions: I. Some A are C. II. No A is C.
  1. Only I follows.
  2. Only II follows.
  3. Either I or II follows.
  4. Neither I nor II follows.
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Answer: C. Either I or II follows.
From statement 1 (All A are B) and statement 2 (Some B are C), there is no definite conclusion about the relationship between 'A' and 'C'. It is possible that 'Some A are C' (e.g., if the 'some B' that are 'C' also include 'A'), and it is also possible that 'No A is C' (e.g., if the 'some B' that are 'C' are entirely outside 'A'). Since both conclusions are individually uncertain, but together they form a complementary pair (Some + No) covering all possibilities, one of them must be true. Therefore, either conclusion I or II follows.
Q7. Statements: 1. All metals are alloys. 2. Some alloys are minerals. 3. No mineral is a gas. Conclusions: I. Some alloys are not gases. II. Some metals are minerals. III. All gases are alloys.
  1. Only I follows.
  2. Only I and II follow.
  3. Only I and III follow.
  4. All I, II and III follow.
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Answer: A. Only I follows.
From statement 2 (Some alloys are minerals) and statement 3 (No mineral is a gas), it means that the part of alloys that are minerals cannot be gases. Therefore, 'Some alloys are not gases'. Thus, Conclusion I follows. From statement 1 (All metals are alloys) and statement 2 (Some alloys are minerals), there is no definite connection established between 'metals' and 'minerals'. So, Conclusion II (Some metals are minerals) does not follow. From statement 3 (No mineral is a gas) and statement 2 (Some alloys are minerals), there is no direct or indirect definite relation between 'all gases' and 'alloys'. It is possible that some gases are alloys, or no gases are alloys, or all gases are alloys, but it is not definite. So, Conclusion III (All gases are alloys) does not follow. Therefore, only conclusion I follows.
Q8. Statements: 1. All rivers are lakes. 2. Some lakes are ponds. 3. Only ponds are oceans. Conclusions: I. Some lakes are oceans. II. All ponds being rivers is a possibility. III. No river is an ocean.
  1. Only I and II follow.
  2. Only II and III follow.
  3. Only I and III follow.
  4. All I, II and III follow.
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Answer: B. Only II and III follow.
From statement 3, 'Only ponds are oceans' means 'All oceans are ponds' and no other entity can be an ocean. I. Some lakes are oceans: From statement 2 (Some lakes are ponds) and the deduction that All oceans are ponds. Lakes and ponds have some overlap. Oceans are a subset of ponds. It is possible that the overlapping part of lakes and ponds contains oceans, but it is not definite. So, Conclusion I does not follow. II. All ponds being rivers is a possibility: From statement 1 (All rivers are lakes) and statement 2 (Some lakes are ponds). It is possible to draw a Venn diagram where all ponds are within the 'rivers' circle (which is itself within 'lakes'). This is a valid possibility. So, Conclusion II follows. III. No river is an ocean: From statement 1 (All rivers are lakes). From statement 3, oceans are exclusively ponds. Since rivers are lakes, and lakes can only partially overlap with ponds, and oceans are *only* ponds, it is impossible for a river to be an ocean. If a river were an ocean, it would have to be a pond, which is not necessarily true for all rivers. Therefore, no river can be an ocean. So, Conclusion III follows. Therefore, only conclusions II and III follow.
Q9. Statements: 1. Only a few students are intelligent. 2. All intelligent are creative. Conclusions: I. Some students are creative. II. Some students are not intelligent. III. All creative are students.
  1. Only I and II follow.
  2. Only II and III follow.
  3. Only I and III follow.
  4. All I, II and III follow.
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Answer: A. Only I and II follow.
The statement 'Only a few students are intelligent' implies two things: (a) Some students are intelligent, and (b) Some students are not intelligent. I. Some students are creative: Since 'Some students are intelligent' (from 1a), and 'All intelligent are creative' (from 2), it follows that 'Some students are creative'. Thus, Conclusion I follows. II. Some students are not intelligent: This is directly implied by the phrase 'Only a few students are intelligent'. Thus, Conclusion II follows. III. All creative are students: From statement 2 (All intelligent are creative) and the deduction that Some students are intelligent. We cannot conclude that all creative are students. It is possible that some creative individuals are not students. Thus, Conclusion III does not follow. Therefore, only conclusions I and II follow.
Q10. Statements: 1. Some dogs are cats. 2. All cats are animals. 3. No animal is a bird. Conclusions: I. Some dogs are animals. II. No cat is a bird. III. All dogs being birds is a possibility. IV. Some animals are not dogs.
  1. Only I, II and III follow.
  2. Only I, II and IV follow.
  3. Only II, III and IV follow.
  4. All I, II, III and IV follow.
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Answer: B. Only I, II and IV follow.
I. Some dogs are animals: From statement 1 (Some dogs are cats) and statement 2 (All cats are animals). Since some dogs are cats, and all cats are animals, it follows that 'Some dogs are animals'. Thus, Conclusion I follows. II. No cat is a bird: From statement 2 (All cats are animals) and statement 3 (No animal is a bird). Since all cats are part of animals, and no animal is a bird, it means 'No cat is a bird'. Thus, Conclusion II follows. III. All dogs being birds is a possibility: From statement 1 (Some dogs are cats). From statement 2 (All cats are animals). From statement 3 (No animal is a bird). This means the 'cats' part of dogs cannot be birds. If 'All dogs were birds', then the 'cats' part of dogs would also have to be birds, which contradicts 'No animal is a bird'. Therefore, it is NOT possible for all dogs to be birds. Thus, Conclusion III does not follow. IV. Some animals are not dogs: From statement 1 (Some dogs are cats) and statement 2 (All cats are animals). This implies 'Some animals are dogs' (specifically, the cats). However, the set of 'cats' is a subset of 'animals'. It is not stated that all animals are cats. Therefore, there must be some animals that are not cats, and thus not dogs. Thus, Conclusion IV follows. Therefore, only conclusions I, II and IV follow.
Q11. Statements: 1. Some plants are trees. 2. All trees are flowers. 3. No flower is a fruit. Conclusions: I. Some plants are flowers. II. No tree is a fruit. III. All plants being fruits is a possibility.
  1. Only I and II follow.
  2. Only II and III follow.
  3. Only I and III follow.
  4. All I, II and III follow.
Show answer
Answer: A. Only I and II follow.
I. Some plants are flowers: From statement 1 (Some plants are trees) and statement 2 (All trees are flowers). Since some plants are trees, and all trees are flowers, it follows that 'Some plants are flowers'. Thus, Conclusion I follows. II. No tree is a fruit: From statement 2 (All trees are flowers) and statement 3 (No flower is a fruit). Since all trees are part of flowers, and no flower is a fruit, it means 'No tree is a fruit'. Thus, Conclusion II follows. III. All plants being fruits is a possibility: From statement 1 (Some plants are trees). From statement 2 (All trees are flowers). From statement 3 (No flower is a fruit). This means the 'trees' part of plants cannot be fruits. If 'All plants were fruits', then the 'trees' part of plants would also have to be fruits, which contradicts 'No tree is a fruit'. Therefore, it is NOT possible for all plants to be fruits. Thus, Conclusion III does not follow. Therefore, only conclusions I and II follow.
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