Question

The question contains six statements followed by four sets of combination of three. Choose the set in which the statements are logically related.

Statements:
(i) All frogs are amphibians.
(ii) All amphibians are not frogs.
(iii) All amphibians are cold blooded.
(iv) All frogs lay eggs.
(v) All amphibians lay eggs.
(vi) Frogs are cold blooded.

• A. i, iii, vi
• B. i, iv, v
• C. i, ii, v
• D. ii, v, iv

Hint:

Two of the statements should nest one class inside another and then inside a third. Track which class appears in both premises and then disappears.

Answer 1

The Correct Option is A

The task is to spot which three statements form a real argument, that is two premises and the conclusion they produce. Treat the words as pure classes and ignore what you know about frogs from biology class, since the logic must stand on the given statements alone.

1. Option (A), i, iii, vi: Frogs fall inside the amphibian class by (i). Amphibians fall inside the cold blooded class by (iii). Nesting one inside the other places frogs inside the cold blooded class, which is exactly (vi). The linking term, amphibians, appears in both premises and vanishes from the conclusion, just as a clean syllogism requires. Valid.
2. Option (B), i, iv, v: Frogs are amphibians and frogs lay eggs. Frogs are only one part of the amphibian class, so this supports only some amphibians lay eggs. Jumping to all amphibians lay eggs pushes a property of a part onto the whole, which is not permitted.
3. Option (C), i, ii, v: Neither (i) nor (ii) mentions eggs at all, so a conclusion about egg laying cannot appear from nowhere. Fails.
4. Option (D), ii, v, iv: To get from all amphibians lay eggs down to all frogs lay eggs you need the premise that frogs are amphibians, and that is statement (i), which is not in this set. Statement (ii) does not do that work. Fails.

Only option (A) forms a complete and valid chain, so it is the answer.

Let us summarize:

• Chain the classes: frogs inside amphibians, amphibians inside cold blooded, so frogs inside cold blooded.
• A property true of a subset, like frogs laying eggs, cannot be pushed up to the whole class of amphibians.
• A conclusion can only use terms that already appear in the premises.

So the correct set is i, iii, vi.