If the proposition 'Some fishes are not amphibians' is given as false, then which of the following propositions can be immediately inferred to be true?

1.No amphibians are fishes

2.All fishes are amphibians

3.No fishes are amphibians

4.Some fishes are amphibians

A1 & 3 only

B3 & 4 only

C2 & 4 only ✓ Correct

D4 only

Correct answer: (C) 2 & 4 only

Explanation

Statements 2 and 4 both come out true when the O proposition is false.

The given O Some fishes are not amphibians is declared false.

The contradictory of a false O is its A, All fishes are amphibians, which is Statement 2.

From that true A, subalternation gives the I Some fishes are amphibians, which is Statement 4.

The two E statements are then false, so only Statements 2 and 4 are true.

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