algebra

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algebra

by ash4gmat » Sat Aug 27, 2016 2:32 am
Q.Is int x divisible by 6?
1. x+3 is div by 3
2.x+3 is odd

OA is C

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by GMATGuruNY » Sat Aug 27, 2016 2:46 am
ash4gmat wrote:Q.Is int x divisible by 6?
1. x+3 is div by 3
2.x+3 is odd
Statement 1:
x+3 = 3, 6, 9, 12, 15, 18, 21, 24...
Subtracting 3 from all of the values above, we get the following options for x:
x = 0, 3, 6, 9, 12, 15, 18, 21...
If x=0, then x is divisible by 6. (0 is divisible by every integer.)
If x=3, then x is NOT divisible by 6.
INSUFFICIENT.

Statement 2:
x+3 = 1, 3, 5, 7, 9, 11, 13, 15...
Subtracting 3 from all the values above, we get the following options for x:
x = -2, 0, 2, 4, 6, 8, 10, 12...
If x=0, then x is divisible by 6.
If x=2, then x is NOT divisible by 6.
INSUFFICIENT.

Statements combined:
Statement 1: x = 0, 3, 6, 9, 12, 15, 18, 21, 24
Statement 2: x = -2, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18...
Only the values in blue satisfy both statements:
0, 6, 12, 18...
In every case, x is divisible by 6.
SUFFICIENT.

The correct answer is C.
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