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Question

Which of the following statements are logically equivalent ?

 A. Some fishes are not amphibians. 

B. Some fishes are amphibians.

 C. Some fishes are non-amphibians. 

D. Some non-amphibians are not non-fishes. 

Choose the correct answer from the options given below:

This question was previously asked in
UGC NET 2022 Paper 1 Question Paper (22-Oct-2022) (Shift 2)
The correct answer is

A, C and D only

To determine which statements are logically equivalent, let's analyze each option:

  1. Statement A: "Some fishes are not amphibians."
    This means there exists at least one fish that does not belong to the category of amphibians.
  2. Statement B: "Some fishes are amphibians."
    This implies there exists at least one fish that is also an amphibian.
  3. Statement C: "Some fishes are non-amphibians."
    This can be rephrased as saying that there is at least one fish that does not belong to the category of amphibians, which is essentially the same as Statement A.
  4. Statement D: "Some non-amphibians are not non-fishes."
    By negating "non-fishes," we get "Some non-amphibians are fishes." This is logically equivalent to stating that there are some non-amphibians that are indeed fishes, which can be seen as similar to Statement A.

By analyzing the statements:

  • Statement A and Statement C are logically equivalent because they both convey that not all fishes are amphibians; some are not.
  • Statement D can be interpreted to support Statement A, as it implies the existence of fishes outside the amphibian category, aligning with Statement A's assertion.
  • Statement B contradicts both A and C since it states that some fishes are amphibians, the opposite of what A and C assert.

Therefore, the logically equivalent statements are A, C, and D. This demonstrates a correct understanding of the logical relationships and equivalence between propositions.

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Similar Questions

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    B. Categorical Proposition
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Important Questions from Structure of Categorical Propositions

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    Choose the correct answer from the options given below :

  5. Match List I with List II

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