A chain of three — Syllogisms Aptitude Question
A chain of three: Statements: All pencils are pens. All pens are markers. All markers are erasers. Conclusions: I. Answer and worked solution on CodeKairo.
- Topic: Syllogisms
- Section: Logical Reasoning
- Difficulty: Medium
- Time target: 75 seconds
Question
Statements:
- All pencils are pens.
- All pens are markers.
- All markers are erasers.
Conclusions: I. All pencils are erasers. II. All erasers are pencils.
Which conclusion follows?
Options
- Only I
- Only II
- Both
- Neither
Show the answer and the worked solution
Correct answer: A. Only I
Worked solution
- The chain gives pencils ⊂ pens ⊂ markers ⊂ erasers, so all pencils are erasers: I follows.
- II reverses the whole chain and is invalid.
Answer: Only I.
The idea
Longer chains work exactly like short ones. Write the inclusions in a single line and read off the end points.
Shortcut. An all-chain carries forwards only: pencils → erasers holds, and II, the whole chain reversed, goes at once.
Common trap. "Both" — accepting II, the full reversal of the chain; erasers may include many things that are not pencils.