Feathers and swimming — Syllogisms Aptitude Question
Feathers and swimming: Statements: All birds have feathers. Some creatures with feathers can swim. Conclusions: I. Answer and worked solution on CodeKairo.
- Topic: Syllogisms
- Section: Logical Reasoning
- Difficulty: Hard
- Time target: 105 seconds
Question
Statements:
- All birds have feathers.
- Some creatures with feathers can swim.
Conclusions: I. Some birds can swim. II. All creatures with feathers are birds.
Which conclusion follows?
Options
- Only I
- Only II
- Both
- Neither
Show the answer and the worked solution
Correct answer: D. Neither
Worked solution
- The swimming feathered creatures might all lie outside the bird group, so I does not follow.
- II reverses 'all birds have feathers' and is invalid.
- Neither follows.
Answer: Neither.
The idea
Judge only what the statements force, not what you know about the world. Real-world knowledge that ducks swim is irrelevant to the logic.
Shortcut. Put the swimming feathered creatures in the feathered-but-not-bird region and I fails; II reverses 'all birds have feathers', so it fails too.
Common trap. "Only I" — using the real-world fact that some birds, like ducks, swim; the statements alone allow every swimmer to be a non-bird.