Bunuel
If \(x\) is a positive integer and the product of any two distinct positive factors of \(x\) is odd, which of the following must be true?
I. \(x\) is an odd prime.
II. \(x^2\) is odd.
III. \(x\) is the square of an odd number.
A. I only
B. II only
C. III only
D. I and II only
E. II and III only
Quote:
the product of any two distinct positive factors of \(x\) is odd
Inference: x is an odd number, as all the factors of x are odd.
Answer choice elimination
I. \(x\) is an odd prime.All we know is that x is an odd integer. x could be a prime number, however, it is not necessary that \(x\) is a prime number.
II. \(x^2\) is odd.We know that \(x\) is an odd integer. Hence, \(x^2\) is also odd.
III. \(x\) is the square of an odd number.Just like I, this could be true. However, the statement is not always true.
For example: if x = 3, x is not a square of an odd number.
Option B