Strategy for Data Sufficiency

Question

Hi guys,

This is my first post on the forum although I've been around for a couple of years mainly following the latest news on B-Schools.

Short Profile:
Nationality: British
Age: 24
Graduated in 2012 with BEng (Hons) Mechanical Engineering from low-mid tier University in UK. First-class with honours (top of class in final year)
Current: MSc Engineering Management in joint degree programme at two top universities in mainland Europe.
I did a year internship (or placement) and worked for another year as an Account Manager before starting the two-year Masters.

I toyed with the idea of taking the GMAT in 2012 but had to shelve the plans. Anyway, earlier this month, I finally decided to take on the GMAT while I'm a student with perhaps more leisure time.

My primary reason for taking the GMAT is not for B-schools, but it is part of my plans in the next three years. I gathered from checking out applications to top-tier consultancy companies they often ask for GMAT scores and my aim is to apply to a couple of these companies later on this year before my graduation next year.

I already had the books purchased and started on 16th May. I drew up a 3-month study plan using the templates on the forum, started reading a fiction book and did a mock GMAT to get an idea of my starting point (Q35, V27) and subsequently started with the Quant part (using Kaplan Math Workbook, OG Quant and OG13). My aim is to score an overall of 710+ so I have a lot of work to do. I found the Problem Solving fairly straightforward, going from 65% to scoring 91%+ after 10 days of recap on Maths basics I probably haven't used in 6 years.

For the Data Sufficiency, I know its only been a couple of weeks work but I've had no luck with this section, scoring 12/25 & 10/25 in the questions at the end of Kaplan Workbook (by the way, really useful book). I get a feeling I'm doing something fundamentally wrong or my approach is not right (or I'm just plain stupid :-D

).
I'm about to start on the OG Quant 2nd Ed book but would really appreciate some advice on what I can do better or perhaps a change in approach.

). I'm about to start on the OG Quant 2nd Ed book but would really appreciate some advice on what I can do better or perhaps a change in approach.

mikemcgarry · Answer

Dear ZF , I'm happy to respond. :-)

First of all, you are NOT plain stupid!! GMAT DS is an unusual beast. It takes a little time to get your head wrapped around it --- it's VERY different from traditional math problems (GMAT PS is much more traditional). Once you understand it, it's easy and fun, but don't blame yourself that you haven't fully understood the format yet. It takes a little while to get exactly what is going on and what is being asked. Here's a blog that addresses the philosophy behind GMAT DS and how it's different from traditional math: https://magoosh.com/gmat/2012/introducti ... fficiency/ Here are a couple blogs that address some basics of DS strategy: https://magoosh.com/gmat/2013/gmat-data- ... ency-tips/ https://magoosh.com/gmat/2012/gmat-data- ... trategies/ Here are some DS practice questions: https://magoosh.com/gmat/2013/gmat-sampl ... questions/ As I am sure you appreciate, math is not a spectator sport: one learns it only by doing it, and the same is true of GMAT DS. There are tons of DS questions already posted on GMAT club --- read them, and pay attention to how the experts approach them, what choices they make. If anything is unclear about a particular problem, why do we consider this and not that, then that's an excellent question to ask. Feel free to send me a private message with a link if you would like my input on a particular problem. It's only by asking the very specific contextual questions about what you don't get that you will resolve your understanding and have the "aha!" moments that you need. Does all this make sense? Mike :-)

ZF · Answer

Really appreciate your input Mike. The tip on using elimination/guessing will certainly add one or two points to my scores and my next aim to keep all the tips in mind as I start the OG Quant DS section :-D

Thanks again !

Thanks again !

dabral · Answer

@ZF

The fundamentals of math that are not tested on the GMAT are fairly basic, especially for someone with an engineering background. However, GMAT data sufficiency trips up every one, especially in the beginning. I have had my share of frustration with it as well when I first started. My recommendation would be to start with the easy ones first, and using the Official Guide Quant review is a great idea. In fact, I would recommend you to stick to only official GMAT questions for practice, the key reason is that one needs to get used to the format and style of these questions and the GMAT writers have a very consistent pattern. Once you start to pay close attention to the structure of these problems, it gets easier to not fall for the standard traps. And don't fret too much about making mistakes, everyone makes tons of mistakes in the beginning, just make sure you learn from them.

Cheers,
Dabral

mikemcgarry · Answer

I just want to commend dabral on some very wise words. Early on in your studying, making mistakes is not a sign that something is wrong. Mistakes are supposed to happen. Here's a GRE blog I wrote about this very point: https://magoosh.com/gre/2013/good-i-got-it-wrong/ I hope this helps! Mike :-)

ZF · Answer

Thanks dabral and Mike. It does seem to be a problem of shifting my mindset from problem solving style questions.

Really found the responses very helpful, I'm just over two weeks into my study plan so hopefully I can apply the right techniques going forward. I'm still yet to discover patterns or structure but perhaps with more questions that will come.

AbhiJ · Answer

Official Guide present a Flow Chart to solve DS problems. I believe that's the best strategy. It's better than AD/BCE strategy advocated by all Test Prep companies. AD/BCE is good only when you cannot solve the problem completely and have to guess. Here AD/BCE will improve your chances of guessing.

ZF · Answer

Thanks AbhiJ, I have found the short guide in the OG quite helpful, I'm doing a little better now compared to when I posted the first message, but still not quite hitting the top echelons. On a side note, going through the past questions on OG Quant 2nd Edition, what percentage should I be scoring in these questions if my aim is 700+?

Appreciate any advice.

Appreciate any advice.

AbhiJ · Answer

If you are targeting above Q48, then you should try to get ~ 90% correct.
For DS, my suggestion would be to slow down your process a bit even if you take 3-4 mins on some problems, its like practicing a golf swing once you get the technique right your speed would improve automatically.

Your solution should look something like

# Stmt 1: Sufficient/Not Sufficient

# Stmt 2: Sufficient/Not Sufficient

Once you have done the above, you would arrive at the solution when your answers are A, B, D.

One more step and you know if the answer is C or E, that step is mentioned below.

# Stmt 1 & Stmt 2 together.

mikemcgarry · Answer

Dear ZF , AbhiJ gave you some good advice. I will just add some cautions. Yes, perhaps allows yourself a little more time as you are practicing, but do not fall into the bad DS habit of doing full calculations for something when all you need to do is answer the sufficiency question. That is a huge trap. For example, if the prompt question says, " What does y equal ?" and the first statement is something like " 17y + 137 = 528 ," then the worst thing in the world you could do is go through all the arithmetic to find the value of y. We have an equation that we could solve for y if we wanted to. BAM! Right there, that's sufficiency. No reason in the world to perform the steps to solve that equation. Taking a little more time at the beginning is fine, but if you have high score aspirations, you need to get into high efficiency mode very quickly. Part of scoring a 700+ means, among other things, that you instantly see the efficient solutions to many Quant questions and are not fooled by the long drawn-out calculation trap that many questions present. It helps to have all the fundamental math at your fingertips. Here are some math flashcards: https://gmat.magoosh.com/flashcards/math/ In order to get anywhere near 700, you have to be a superstar on every question type. Here are some challenging practice problems: https://magoosh.com/gmat/2013/gmat-data- ... obability/ https://magoosh.com/gmat/2013/gmat-quant ... qualities/ You will find a great deal on that free blog that can help you. Mike :-)

ZF · Answer

Appreciate the input AbhiJ and Mike. It's always very interesting to try out different approaches. Upon reflection, my DS understanding is much improved since that first post, so the tips really have been of help. Although, I've now started the verbal section, my plan is to keep on top of Quant, especially DS by doing a couple of sessions a week just to iron out few more errors.

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