Which of the following is a counterexample for the statement
For all integers x, if x is not prime then x is divisible by 2
18, 2, 45, 15, 100, 23
What I tried is to do the opposite of this statement, so: For all integers x, if x is a prime number then it is NOT divisible by 2
Im think the only logical answer is 23, because 23 is NOT divisible by 2 and 23 is a prime number
A counterexample is something that proves the statement wrong. For example, "All swans are white" has the counterexample of a black swan, because it is a swan that is not white.
Here, "For all integers x, if x is not prime then x is divisible by 2". So you need an integer such that if it is not prime it is not divisible by 2. Which of the possible numbers has such a property?