Syllogism Flashcards

Statements: Some files are folders. All folders are drives. No drive is a disk. Conclusions: I. Some files are not disks. II. No folder is a disk. Which conclusion(s) follow?

Answer: Both I and II follow

All folders are drives and no drive is a disk, so no folder is a disk (II follows); some files are folders → drives, and no drive is a disk, so some files are not disks (I follows).

Statements: All trains are vehicles. Some vehicles are aeroplanes. Conclusions: I. Some trains are aeroplanes. II. Some aeroplanes are vehicles. Which conclusion(s) follow?

Answer: Only II follows

Some vehicles are aeroplanes, so by conversion some aeroplanes are vehicles (II follows); the vehicles that are aeroplanes may not be trains, so Conclusion I does not necessarily follow.

Statements: No mango is a banana. Some bananas are oranges. Conclusions: I. Some oranges are not mangoes. II. No mango is an orange. Which conclusion(s) follow?

Answer: Only I follows

Some bananas that are oranges are definitely not mangoes (since no mango is a banana), so Conclusion I follows; it is possible that some mangoes are oranges through a path not involving bananas, so Conclusion II does not follow.

Statements: All coins are notes. All notes are cheques. All cheques are drafts. Conclusions: I. All coins are drafts. II. All notes are drafts. Which conclusion(s) follow?

Answer: Both I and II follow

Coins → notes → cheques → drafts, so all coins are drafts (I follows); notes → cheques → drafts, so all notes are drafts (II follows).

Statements: Some kings are queens. No queen is a jack. Conclusions: I. Some kings are not jacks. II. All jacks are kings. Which conclusion(s) follow?

Answer: Only I follows

Some kings are queens and no queen is a jack, so those king-queens are not jacks, meaning some kings are not jacks (I follows); there is no basis to conclude all jacks are kings (II does not follow).

Statements: All bowls are plates. Some plates are cups. No cup is a glass. Conclusions: I. Some bowls are not glasses. II. Some plates are not glasses. Which conclusion(s) follow?

Answer: Only II follows

Some plates are cups and no cup is a glass, so some plates are not glasses (II follows); there is no definite path connecting bowls to cups/glasses, so Conclusion I does not necessarily follow.

Statements: No stone is a wood. All woods are metals. Some metals are plastics. Conclusions: I. Some plastics are not stones. II. No stone is a metal. Which conclusion(s) follow?

Answer: Only I follows

All woods are metals and no stone is a wood — the metal-woods are not stones, and since some metals are plastics, some plastics (through the wood-metal path) are not stones, so Conclusion I follows; stones may still be metals through other means, so Conclusion II does not definitively follow.