Vincen wrote: ↑Sat Dec 04, 2021 7:42 am
Is the integer \(n\) even?
(1) \(n - 5\) is an odd integer.
(2) \(\dfrac{n}5\) is an even integer.
Answer:
D
Source: GMAT Paper Tests
Some important rules:
1. ODD - ODD = EVEN
2. EVEN - ODD = ODD
3. ODD - EVEN = ODD
4. EVEN - EVEN = EVEN
5. (ODD)(ODD) = ODD
6. (ODD)(EVEN) = EVEN
7. (EVEN)(EVEN) = EVEN
Target question: Is integer n even?
Statement 1: n – 5 is an odd integer
Since 5 is ODD, statement 1 is saying: n - ODD = ODD
From
rule #2 above, we can conclude that n is EVEN
So,
the answer to the target question is "YES, n IS even"
Since we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: n/5 is an even integer.
First multiply both sides by 5 to get: n = (5)(some EVEN integer)
Since 5 is ODD, we statement 2 is saying: n = (ODD)(EVEN)
From
rule #6 above, we can conclude that n is EVEN
So,
the answer to the target question is "YES, n IS even"
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: D
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
