Solving DS questions

Question

Do we really need to solve DS questions using pen and paper or just thinking on mind that option A would suffice and moving ahead is better?

In my opinion, for hard and medium level questions one might need to use pen and paper.

And I am taking more time on percent and TSD, time work DS problems more time..any valuable suggestions would help.

And would like to know from which topic more of DS questions come
No one can predict this, GMAC has a vast pool of questions.

LeoN88 · Answer

LoneSurvivor · Answer

I think it is better to use Pen and Paper while solving DS questions because the DS questions get very much convoluted as you move forward in the test and you may forget consider few cases as DS is all about finding all possibilities

AndrewN · Answer

Hello,  monikakumar . I just practiced a mixed question set earlier of PS and DS problems, and I know what you mean. Do you have to write everything down? No. Looking at my scratch pad from earlier, I see a lot of random numbers and letters jotted down. However, you definitely want to take account of  exactly  what information is given and  exactly  what the question is asking. (Do not assume an unknown is an  integer , for example, if that word is not present.) I often write down intermediary numbers to prevent overloading my working memory, not to mention to simply keep all my facts straight. I like to attack the easier-looking statement first and think of a logical split between AD/BCE (if I start with Statement (1)) or BD/ACE. To be honest, sometimes Statement (2) just looks simpler, and I would rather narrow the answer pool using a simpler approach than hack through a tougher statement that might leave me unsure and then move on to the other statement just because it was there. Getting a little momentum going is important on tougher questions, but that is hard to do if you are operating completely on gut instinct.

As for theory, you should check out the topic-by-topic  Ultimate GMAT Quantitative Megathread  for reference. As another member noted above, you cannot really count on seeing x-number of content-specific DS questions, so a broad approach to your studies would serve you best.

If you have further questions, feel free to ask. Good luck with your studies.

- Andrew

monikakumar · Answer

Thanks all for your response. is practising all questions from og will be enough?

AndrewN · Answer

It really depends on your target score,  monikakumar . Many students rush through OG questions without a firm foundation in theory, and then they find themselves in a bind looking for high-quality questions. Note, too, that the OG does not exactly order the questions for you by content, and many students find it useful to drill the same concept over and over to increase proficiency or achieve mastery in a certain topic. I think at the very least, you should consider supplementing your OG questions with those from the GMAT Club forum, since the latter do provide content-specific threads. I just want to spare you the frustration of exhausting the OG, making the same mistakes in problem after problem, and then feeling as if you cannot get your hands on questions that truly mimic those you will see on the test.

If you have further questions, feel free to ask.

- Andrew

CrackverbalGMAT · Answer

Hello Monika,

The  first thing I advise students to do  when I start teaching Quant for any competitive exam is  to quit doing mental math and put pen to paper.  Does this mean that you have to do every single calculation on paper? That would be a clear NO.
 
You need to be prudent to understand that  there’s a thin line between the two .

Do you want to solve a quadratic equation in your mind? Maybe, maybe not.
 
What about a hard question (irrespective of DS or PS) on Inequalities / Remainders? Definitely not.

What about multiplying two numbers/finding out the LCM or HCF/ squares/adding numbers? Go ahead, by all means.

A lot of times, students end up flipping the above line items on its head and end up doing mental math with the equations/expressions while doing the simpler calculations on paper. Really, it should be the other way round, isn’t it?

I would recommend  jotting down important information  from a DS question  as you read the question . 
  This will ensure that you don’t spend extra time on FIRST reading the whole question and then coming back to take down information.

It will also ensure that it slows you down and calms your nerves.

Added benefit is you will have all the information you need in front of you to break down the question stem and frame equations/expressions/inequalities.

Last, but not the least, it will reduce the number of wrong assumptions that students very often make when solving DS questions mentally.

As you write down information and start solving the question,  write down the options on one side of the scratch paper .  Cross out the wrong answers as you eliminate them . This way, you will not have to remember which options have not been eliminated. This will reduce your mental effort and time taken.

In topics like Time & Distance, P&C, Probability, Overlapping sets and Geometry, putting pen to paper is inevitable . The more you write, the better chances of you getting the answer right. 
So,  I hope that answers your main question  on whether you should try to solve DS questions mentally.  The answer  to that  is a clear NO .

On topics like percents, TSD and rates ,  use your knowledge of numbers and ratios along with the fundamental concepts  related to that topic to develop cases.  Write down the cases  (see, writing comes up again) and then solve the problem. Going by your main question, I have a feeling that you are actually trying to solve them mentally. Also remember to strengthen your concepts in these areas because all these topics are concept-oriented.

The last question  of yours is probably  the hardest one to answer because I do not have one . I wish I could tell put a finger on a particular topic which gives more questions than the others, but clearly, that’s impossible to do on a test like the GMAT.

Hope that helps!

Solving DS questions

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards