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If n is an integer, which of the following must be even?
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17 Aug 2020, 10:40
17 Aug 2020, 10:40
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If n is an integer, which of the following must be even?
(A) n+1
(B) n+2
(C) 2n
(D) 2n +1
(E) n^2
(A) n+1
(B) n+2
(C) 2n
(D) 2n +1
(E) n^2
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Re: If n is an integer, which of the following must be even?
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17 Aug 2020, 11:07
17 Aug 2020, 11:07
1
Carcass wrote:
If n is an integer, which of the following must be even?
(A) n+1
(B) n+2
(C) 2n
(D) 2n +1
(E) n^2
(A) n+1
(B) n+2
(C) 2n
(D) 2n +1
(E) n^2
APPROACH #1: Apply the definition of "even
An integer is even if we can rewrite it as 2k for some integer k.
For example, we know that 14 is even since we can rewrite it as (2)(7)
Likewise, if n is an integer, then 2n must be an integer.
Answer: C
APPROACH #2: Test values
If x = 3, then we get:
(A) n+1 = 3+1 = 4, which is even. Keep.
(B) n+2 = 3+2 = 5, which is odd. ELIMINATE.
(C) 2n = (2)(3) = 6, which is even. Keep.
(D) 2n +1 = 2(3) + 1 = 7, which is odd. ELIMINATE.
(E) n^2 = 3^2 = 9, which is odd. ELIMINATE.
We are left with the answer choices A and C, so we'll test another value of x
If x = 4, then we get:
(A) n+1 = 4+1 = 5, which is odd. ELIMINATE.
By the process of elimination, the correct answer is C
Cheers,
Brent
gmatclubot
Re: If n is an integer, which of the following must be even? [#permalink]
17 Aug 2020, 11:07
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