aamlani wrote:
If k and n are integers, is n divisible by 7?
(1) n-3 = 2k
(2) 2k - 4 is divisible by7
[Reveal] Spoiler:
Need help understanding the answer to this question please!
*** I understand why each statement alone is insufficient, however, in the GMAT quant review book it substitutes n-3 into 2k-4 in (2). According to the answer in the book then, (n-3), or n-7, is divisible by 7. This means that n-7 = 7q for some integer q. Therefore, n = 7q + 7 = 7(q+1)
I DON'T GET THIS.
When n-3 is substituted into equation (2), shouldn't it read 2(n-3)-4 is divisible by 7? Which would mean that 2n-10 is divisible by 7? What happens to the 2? Confused.
*** I understand why each statement alone is insufficient, however, in the GMAT quant review book it substitutes n-3 into 2k-4 in (2). According to the answer in the book then, (n-3), or n-7, is divisible by 7. This means that n-7 = 7q for some integer q. Therefore, n = 7q + 7 = 7(q+1)
I DON'T GET THIS.
When n-3 is substituted into equation (2), shouldn't it read 2(n-3)-4 is divisible by 7? Which would mean that 2n-10 is divisible by 7? What happens to the 2? Confused.
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