susha0df wrote:
If a and b are integers and a is even, what is the value of a - b?
(1) a < 3
(2) a/b=2/7

Target question: What is the value of a - b?

Statement 1: (1) a < 3
Since we don't know the value of a or b, there's no way to find the value of a - b.
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: a/b = 2/7
There are many pairs of values that meet this condition. Here are two:
Case a: a = 2 and b = 7, in which case a - b = -5
Case b: a = -2 and b = -7, in which case a - b = 5
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined:
There are still many pairs of values that meet this condition. Here are two:
Case a: a = 2 and b = 7, in which case a - b = -5
Case b: a = -2 and b = -7, in which case a - b = 5
Since we still cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent

susha0df wrote:
So i guess when a qs simply says about even or odd integers - we should not limit to +ve integers. For

Exactly. The test-makers often like to test whether or not students recognize that evens and odds extend to negative numbers, as well as zero being an even number.

Cheers,
Brent