Question

Assuming x and y are two odd numbers and x/y is an integer. Which of the following statements are true?

1: x + y is odd.
2: xy is odd.
3: x/y is odd.
4: x-y is odd.

A: 1 and 2 only.
B: 1 and 3 only.
C: 2 and 3 only.
D: 2, 3, and 4 only.
E: 2 and 4 only.​

Answer 1

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Answer:

C: 2 and 3 only.

Explanation:

We know the sum or difference of two odd numbers is even, eliminating choices (1) and (4).

The product of two odd numbers is odd, so (2) is one of the true statements.

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Let x/y = k, where x and y are both odd. Then x = ky. If k is even, then x is even, a contradiction. So, k must be odd. The integer ratio of two odd numbers is odd, so (3) is one of the true statements.

Only statements (2) and (3) are true.