Quick question about Data Sufficiency rule

Expert replies

gameson: Newbie | Next Rank: 10 Posts; Posts: 2; Joined: Sat Aug 09, 2008 4:55 pm

by gameson » Sat Aug 09, 2008 5:01 pm

I have a question.

Lets say the question is asking wheter a number is an odd integer, or whether x > y, something like that

then in statement 1, it shows a clue that statement 1 is giving enough information to answer the question, BUT the answer is wrong (i.e if the Q is asking if it's an odd integer, then in statement 1, it's sufficient to answer the Q but the answer is an even integer. Does it mean statement 1 is sufficient? another example is Q is whether x > y. Statement 1 is giving enough clue but the answer is x < y)

My understanding is that if the statement is giving enough clue but answering it wrong, so it means it's sufficient enough.

BUT i m practicing using the official GMAT review, and it says otherwise. When the answer is wrong, that means the statement is not sufficient.

I am confused....

Like this post

Source: Beat The GMAT — Data Sufficiency | Sat Aug 09, 2008 5:01 pm

2008: Senior | Next Rank: 100 Posts; Posts: 32; Joined: Tue Apr 08, 2008 10:09 am; Thanked: 4 times

by 2008 » Sat Aug 09, 2008 5:12 pm

there are 2 kind of questions in data sufficiency:

- the one that ask to find the result/number of a problem
- the one where you have to answer YES or NO

the way i approach it is that if it is a YES or NO one i write Y N at the top of my notebook. it's very helpful.

once u ve actually determined this then the DS questions are about "do you have sufficient data to: find the result/answer YES or NO" ?

in the first case if you have sufficient data to find the number, then is ok

in the second case you need sufficient data either for answering Y or for answering NO. but once you have sufficient data, no matter if for saying Y or N, then is ok.

both in the first and in the second case, it is NOT ok when you DONT have sufficient data to give an answer

getting back to the way you posed the problem, your "understanding" is right

i'm sure you can find much better of answers than mine in this forum

and googling GMAT DATA SUFFICIENCY

Like this post

GMAT/MBA Expert

Ian Stewart: GMAT Instructor; Posts: 2623; Joined: Mon Jun 02, 2008 3:17 amFollowed by: 355 members; Location: Montreal; Thanked: 1090 times; GMAT Score:780

Re: Quick question about Data Sufficiency rule

by Ian Stewart » Sun Aug 10, 2008 4:18 am

gameson wrote:
BUT i m practicing using the official GMAT review, and it says otherwise. When the answer is wrong, that means the statement is not sufficient.

I'm curious- where did you read that?

On DS, your task is to determine whether the statements give you enough information to give a definite answer to the question. It doesn't matter if the answer to the question is 'yes' or 'no', just as long as you can be 100% certain of the answer. That said, it is very rare to find a real GMAT DS question where you have sufficient information for a yes/no question, but the answer turns out to be 'no', so you probably won't need to worry about this. There is, for example, only one such question in the Official Guide.

For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com

Like this post

gameson: Newbie | Next Rank: 10 Posts; Posts: 2; Joined: Sat Aug 09, 2008 4:55 pm

by gameson » Sun Aug 10, 2008 7:16 am

Thanks for the reply, Ian. I read that exactly from the GMAT Official Review as the Official is the only practice test that I try so far, and it pissed me off. It's sufficient enough for an answer and it's a NO, but the answer says not sufficient because the answer is wrong. I don't remember the question number, but it has brought to my attention.

Like this post

erjamit: Master | Next Rank: 500 Posts; Posts: 170; Joined: Mon Oct 22, 2007 4:36 am; Thanked: 7 times

by erjamit » Sun Aug 10, 2008 8:18 am

@Ian

There is, for example, only one such question in the Official Guide.

Can you pls tell which question you are talking about.

Thanks
Amit

Like this post

GMAT/MBA Expert

Ian Stewart: GMAT Instructor; Posts: 2623; Joined: Mon Jun 02, 2008 3:17 amFollowed by: 355 members; Location: Montreal; Thanked: 1090 times; GMAT Score:780

by Ian Stewart » Sun Aug 10, 2008 9:43 am

Question 89, in the Orange OG, 11th Ed. Of the 55 yes/no DS questions in the OG for which E is not the right answer, it's the only one where the statements answer a yes/no question with a 'no'.

For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review