Some pens are books — Syllogisms Aptitude Question
Some pens are books: Statements: Some pens are books. All books are papers. Conclusions: I. Some pens are papers. II. Answer and worked solution on CodeKairo.
- Topic: Syllogisms
- Section: Logical Reasoning
- Difficulty: Medium
- Time target: 60 seconds
Question
Statements:
- Some pens are books.
- All books are papers.
Conclusions: I. Some pens are papers. II. All papers are books.
Which conclusion follows?
Options
- Only I
- Only II
- Both I and II
- Neither
Show the answer and the worked solution
Correct answer: A. Only I
Worked solution
- Some pens are books, and all books are papers, so those pens are papers: conclusion I follows.
- Conclusion II reverses an 'all' statement, which is invalid.
Answer: Only I.
The idea
'Some A are B' plus 'All B are C' always yields 'Some A are C'. Reversing an 'all' is the classic trap.
Shortcut. One counter-drawing kills II: draw papers larger than books, so some paper is not a book. I survives every drawing because the pen-books sit inside papers.
Common trap. "Both I and II" — reading 'All books are papers' backwards as 'all papers are books'.