Bombsante wrote:
Hi, If we simplify the equation is question stem, it gives a+b = 2ab. Therefore, the Q is asking "is a+b = 2ab?"
Statement 1 says exactly that, therefore sufficient. Now here is when the doubt arises in my head. The Q is a yes / no Q.
If we are able to answer the Q in a definite Y or a definite N, the statements should be sufficient.
Statement 2 says that a+b = 2. Why is this not sufficient? It does help us in answering "is a+b = 2ab" in a definite no IMO.
I am definitely missing out something,
Bunuel plz help.
Two things:
1. On the GMAT, two data sufficiency statements always provide TRUE information and these
statements never contradict each other. So, if you were right and (2) were also sufficient with a NO answer to the question, then the question would be flawed because we cannot have an YES answer from (1) and a NO answer from (2). The statements in this case would clearly contradict each other.
2. The question asks is a + b = 2ab and (2) says that a + b = 2. But a + b = 2ab and a + b = 2 could be true simultaneously when a = b = 1, and in this case a + b = 2ab would be true, giving an YES answer to the question. While all other values of a and b satisfying a + b = 2, will give a NO answer to the question. So, we can have both a NO and an YES answers, which makes (2) not sufficient.
Hope it helps.
_________________