Question about selecting "D" in a DS problem

[weiyuegao]

Just wondering before we select answer "D" (Either statement is sufficient) on ANY DS problems, do either statement have to lead to the SAME answer?

Ex. Is the integer X between 20 and 26 inclusive?
(1) x is multiple of 9
(2) x = 18

The corret answer is "D", but (1) leads to x = 9. 18, 27...
therefore X is NOT in between 20 and 26 inclusive
(2) leads to x=18 therefore X is NOT in between 20 and 26 inclusive

Notice both (1) and (2) answer the question with "NO". My point is that will there be GMAT DS where correct answer is "D" but (1) leads to some answer and (2) leads to a different answer? althoght either are sufficient but the answers to the problem is different. Do ALL GMAT DS questions which answer is "D" have Both (1) and (2) lead to the same answer ALL THE TIME? Is that a good double check for before anserwing "D"?

Thanks
Wei

[sdola]

The goal is to check which option answers the question.
Here the question is to check if x is between 20 and 26 inclusive. Like you said #1 answers the question if x is between 20 and 26.
#2 Also answers the question. Here we should be concerned about yes or no and not the value of the answer.

[weiyuegao]

Thanks but I think you are missing my point. I understand that the actual answer to the question is irrelavant.

Let me use another example.

What's the value of X?
(1) x=1
(2) 2x=4

Will we ever get these kinda question in GMAT?

or Will all the correct "D" DS questions on the real GMAT be like the following example?

What's the value of X?
(1) x = 1
(2) 2x=2

The goal is to check which option answers the question.
Here the question is to check if x is between 20 and 26 inclusive. Like you said #1 answers the question if x is between 20 and 26.
#2 Also answers the question. Here we should be concerned about yes or no and not the value of the answer.

[weiyuegao]

anyone?

[rajkapoor]

Based on my understanding so far and applying lil foresight , I modestly claim that the answer to your question is "No, there can be no instance where the exact answer varies from statement 1 to statement 2"
[editor: you are correct in spirit, but note that this actually means that the answer to the poster's original question is YES, not NO.]

Situation: Satement 1 - x is 1
Statement 2 - x is 2

Can the above be true?

Reasoning: If your question were to be a GMAT question, then GMAC would be obliged to provide one concrete answer for X for a value question. It cannot provide two different answers(x=1 and x=2) at two different occasions.
In a given set of conditions/constraints , x can only have a specific value.

Why can GMAT not do what you described ?
They cannot create such a scenario because doing that would make their test-making intentions questionable. I think I read somewhere that these questions are tested by outside resources for their validity.

But ultimate question is -
Why Worry about such a situation?
[editor: as the poster stated above, it's actually a checkpoint of sorts: if you wind up getting two different answers from the statements, then you know that something is awry with your approach.]

As an extra excercise for you -

Which of these sentences is correct , if any , else provide the correct sentence structure

Did you see any question leading you to believe that both statements are tricking you to difference answers ?

"Did you see any question that lead you to beleive that both statements are tricking you to different answers ?

Did you see any question that has lead you to believe that both statements tricked you into different answers ?

Did you see any question that lead you to believe that both statements have tricked you into different answers ?

- raj

[weiyuegao]

Thanks Raj for the rather humorous post :D

[rajkapoor]

hope that answered your question.

Realized that my response needs to be moved to sentence correction section.

The sentence
"Based on .... , I .... " has wrong structure.
(OG SC-25 )

[RonPurewal]

Do ALL GMAT DS questions which answer is "D" have Both (1) and (2) lead to the same answer ALL THE TIME? Is that a good double check for before anserwing "D"?

fantastic question.

the answer is absolutely YES -- there must be 100% consistency between the answers yielded by the two statements, if both are individually sufficient.

and, yes, this is a nice way to check for the validity of your solution technique.