Is x + y > 6?

[Vincen]

Is x + y > 6?

(1) x + 2y > 8

(2) 2x + y > 8

The OA is E.

If we take both statements we can add each equation and we'll get 3x+3y>16, so x+y > 5.3333.
So we can conclude that x+y is not greater than 6. So, the answer should be C. Where did I a mistake?

[Brent@GMATPrepNow]

Is x + y > 6?

(1) x + 2y > 8

(2) 2x + y > 8

The OA is E.

If we take both statements we can add each equation and we'll get 3x+3y>16, so x+y > 5.3333.
So we can conclude that x+y is not greater than 6. So, the answer should be C. Where did I a mistake?

Your analysis is perfect.
When we combine the statements, we learn that x+y > 5.3333...
So, x+y could equal 5.5 , in which case x+y is NOT greater than 6
Or x+y could equal 7 , in which case x+y IS greater than 6

Since we cannot answer the target question with certainty, the statements COMBINED are not sufficient.

Answer: E

Cheers,
Brent