DS Help

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DS Help

by vinay1983 » Mon Oct 07, 2013 1:46 am
Hi all,
I have reviewed almost all the wrong answers i got while giving the mocks. I was wrong on most DS questions, which were more of 600+ level.
I need some general tips on doing DS such as what integers or decimals to use for testing numbers or plug in answers (0,1,-1,1/2 etc).So any help, suggestions, tips, mini notes or generic tricks will be helpful.In understand the oddity of my question, but it just that without quant i cannot reach my aspired score.Also if someone can tell me on what not to do, i would be more than happy.Any test day tricks or tips too.

I will be glad to receive your help.
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by mevicks » Mon Oct 07, 2013 4:54 am
Hi Vinay,
I'm no expert on this but here are my 2 cents...

- Most of the time they disguise the original question in the stem. 80% of the time they can be simplified further. This has helped me tremendously to raise my DS accuracy (MGMAT 4th ed. guides had an entire chapter on rephrasing official DS questions. Although I cant find them in the newest ones)

- A friend of mine has advised me to do a vertical scan before jumping onto the calculation part. Some answers can give you a pretty decent idea of which numbers to use as smart numbers.

- This advice, although contrary to what most experts say, is a bit weird one (and I'm trying to implement this in my current preps.): Some questions (Mod, inequalities, quadratic) require that you go ahead and calculate AND THEN plug in the FINAL answer and re verify. This sometimes yields a definite answer! (I got few questions wrong because of this, saw them on MGMAT cats)

- ALWAYS REMEMBER THIS: OFFICIAL GMAT QUESTION STEMS WILL NEVER HAVE TWO STATEMENTS WHICH YIELD TWO DIFFERENT ANSWERS. BOTH (A) AND (B) should give you the same answer (if they are correct, of course) Use this trick to guide your calculation. Sometimes when you evaluate the 2nd statement you can catch hold of any silly mistake done with the first one. (if your answers dont match)

Hope it helps.

Regards,
Vivek

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by theCodeToGMAT » Mon Oct 07, 2013 4:58 am
Hello Vinay,

It happens :) .. It's a stage which each of us goes through.

The strategy which I follow:

- For Inequalities: I always try to restrict myself from using plug-in random method; Rather, I prefer playing with signs "+" & "-". But, that doesn't mean i don't use plug-in method; I do, when the situation demands.

- I always try to re-phrase the DS Question Stem. Many a times question is made complex but infact are not. So, rephrasing can help at times.

- Don't try to judge/jump to conclusion from each statement without knowing what exactly is been asked; I also do so :)

- For whole Quant section, be sure you know useful formulas

- When using plug-in value method.. do try extreme value cases.. as they generally give a better sight of the equation under consideration.
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by Brent@GMATPrepNow » Mon Oct 07, 2013 7:24 am
Hi Vinay,

You may already be aware of this, but if you're looking for extra DS resources, we have a free set of videos that cover everything you need to know: https://www.gmatprepnow.com/module/gmat-data-sufficiency

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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by sana.noor » Mon Oct 07, 2013 9:49 am
why dont u try beat the gmat library? it will really help.
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by rakeshd347 » Mon Oct 07, 2013 1:02 pm
vinay1983 wrote:Hi all,
I have reviewed almost all the wrong answers i got while giving the mocks. I was wrong on most DS questions, which were more of 600+ level.
I need some general tips on doing DS such as what integers or decimals to use for testing numbers or plug in answers (0,1,-1,1/2 etc).So any help, suggestions, tips, mini notes or generic tricks will be helpful.In understand the oddity of my question, but it just that without quant i cannot reach my aspired score.Also if someone can tell me on what not to do, i would be more than happy.Any test day tricks or tips too.

I will be glad to receive your help.
Hi Vinay,

DS is a broad topic but I will try to put some points here.

When you are doing you should take these points in consideration:
1. take one statement at a time and don't let the other statement emphasise the outcome on the other statement.
2. always take the easy statement first( if you think that statement 2 is easy to eliminate or show that not sufficient start with 2)
3. when picking up the number especially with inequality and absolute value questions you need to careful for these 3 ranges -1 to 0, 0 to 1 and more than 1. Most of the time you will get it wrong for not considering these 3 ranges. For example x^2 is will be smaller than x between 0 and 1. So check these ranges when picking up number.
4. Try to make the statement not sufficient rather than sufficient. Try to get the two outcomes from the same statement. Because it is easier to eliminate because of insufficient than prove sufficient.
5. When picking up the number with ratio or percentage pick easy numbers. If you have 3 and 5 in the denominator it will be easy to work with 15 or 30.

These are the things basically i always keep in my mind and it all comes with practise to be honest.

Thanks
Rakesh

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by vinay1983 » Mon Oct 07, 2013 7:20 pm
Rakesh, this is what the doctor ordered!(Imagine my plight that a doctor had to order me this!)
You can, for example never foretell what any one man will do, but you can say with precision what an average number will be up to!