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Read these six conditional claims :

1. If it's an apple, then it's a fruit.
2. If it's a fruit, then it's an apple.
3. It's an apple if it's a fruit.
4. It's a fruit if it's an apple.
5. It's not a fruit if it's not an apple.
6. It's not an apple if it's not a fruit.

Out of these six conditional claims which three claims have the answer as Yes ?

  • A.2, 3, 5
  • B.2, 3, 4
  • C.3, 4, 5
  • D.1, 4, 6

Answer: D

The three true claims are 1, 4, 6.

Every apple is a fruit, but not every fruit is an apple. So any claim equivalent to ‘if apple, then fruit’ is true, and any claim equivalent to ‘if fruit, then apple’ is false.

  • Claim 1 says if apple, then fruit: true.
  • Claim 4, ‘fruit if apple’, says the same thing: true.
  • Claim 6, ‘not an apple if not a fruit’, is the contrapositive of claim 1: true.
  • Claims 2 and 3 both say if fruit, then apple: false. Claim 5, ‘not a fruit if not an apple’, is the contrapositive of that false claim, so it is false too.

Every other option includes at least one of claims 2, 3 or 5.

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