Data Sufficiency

by **Guest** Sat Nov 15, 2008 3:09 pm

Is it always true that both the statements of a DS question, if at they help arriving at the solution, will lead to the same solution/answer?

by **esledge** Sun Dec 07, 2008 5:35 pm

There should always be some value(s) that both statements agree upon. That does not mean that the statements must agree complete, just that they must agree on something.

Valid statements:
(1) x > 2
(2) x > 4
These statements agree on all values x > 4.

(1) x > 2
(2) x = 5.
These statements agree on x = 5. Another way to look at this is that (1) is technically true when x = 5, it's just not as specific as it could be.

(1) x is not odd.
(2) x is not even.
These statements agree on non-integer x values. If x = 2.5, or 1.78, or 5.14, etc, then both statements are true.

Invalid statements:
(1) x > 2
(2) x < -1
There are no value for x that would maintain the truth of both statements. For example, if x = -2, then (2) is true, but (1) is lying. The statements cannot lie to you.

(1) x is odd.
(2) x is even.
There are no numbers that are both odd AND even. One of these statements must be lying.

by **Guest** Mon Dec 08, 2008 2:16 pm

esledge Wrote:There should always be some value(s) that both statements agree upon. That does not mean that the statements must agree complete, just that they must agree on something.

But what if each statement is individually enough to arrive at a solution but yield different answers which don't agree with each other at any point of x (say one arrives at x=2 and other other x=-3), even in that case one is of the statement wrong? Or are there no such cases in GMAT?

for as per the requirements of the question, we are able to get an answer by using either of the conditions individually / independently even if the answers derived are different or don't agree with each other.

by **JonathanSchneider** Wed Dec 17, 2008 2:47 pm

You will never get answers from the two statements that contradict. Therefore, you will NEVER see Statement 1 give you x=3 while Statement 2 gives you x=-3. If you see this, you have made a math error.

However, you could see an overlap. For example:
(1) x = 2, -3
(2) x = -3

In the case shown above, there is not contradiction.