Some books are pens — Syllogisms Aptitude Question
Some books are pens: Statements: Some books are pens. All pens are pencils. Conclusions: I. Some books are pencils. Answer and worked solution on CodeKairo.
- Topic: Syllogisms
- Section: Logical Reasoning
- Difficulty: Medium
- Time target: 75 seconds
Question
Statements:
- Some books are pens.
- All pens are pencils.
Conclusions: I. Some books are pencils. II. All pencils are pens.
Which conclusion follows?
Options
- Only I
- Only II
- Both
- Neither
Show the answer and the worked solution
Correct answer: A. Only I
Worked solution
- Some books are pens, and every pen is a pencil, so those books are pencils: I follows.
- 'All pencils are pens' reverses statement 2 and does not follow.
Answer: Only I.
The idea
'Some A are B' plus 'all B are C' always gives 'some A are C'. Reversing an 'all' is the classic invalid step.
Shortcut. II turns 'All pens are pencils' round, so every option containing II goes at once; I is the standard some + all result.
Common trap. "Both" — accepting II, which reverses 'All pens are pencils'; pencils may include many things that are not pens.