A student claims: *'If is a positive integer and is divisible by 6, then is divisible by 3.'* Which value of is a counterexample?

Answer and explanation

Correct answer: A.

  1. Step 1: For : is divisible by , so these cannot contradict the claim.
  2. Step 2: For : , which is divisible by , but is not divisible by . So is a counterexample.
Answer
.
Why not the others: A counterexample must satisfy the hypothesis (a multiple of for ) and break the conclusion; every multiple of breaks nothing.

Practise more Counterexamples.

Free questions with an explanation for every one, and full timed TMUA mock tests.