Given: n is a positive integerM7MBA wrote:If \(n\) is a positive integer, is \(n\) odd?
(1) \(3n\) is odd.
(2) \(n + 3\) is even.
[spoiler]OA=D[/spoiler]
Source: Official Guide
Target question: Is n odd?
Some important rules:
#1. ODD +/- ODD = EVEN
#2. ODD +/- EVEN = ODD
#3. EVEN +/- EVEN = EVEN
#4. (ODD)(ODD) = ODD
#5. (ODD)(EVEN) = EVEN
#6. (EVEN)(EVEN) = EVEN
Statement 1: 3n is odd
Since 3 is ODD, we are told that (ODD)(n) = ODD
From Rule #4 above, we can conclude that n is ODD
The answer to the target question is YES, n IS odd
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: n + 3 is even
in other words, n + ODD = EVEN
From Rule #1 above, we can conclude that n is ODD
The answer to the target question is YES, n IS odd
Since we can answer the target question with certainty, statement 2 is SUFFICIENT
Answer: D
Cheers,
Brent
