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by Rich Cohen, [email protected] EMPOWERgmat.com
This series of emails and PMs focuses on situations that many Test Takers face during their studies. The names of the original posters have been changed to protect their identities.
The Reality of a 700+ Score
Hi Rich,
I find the 700-800 level Combinatorics and Probability stuff hard. For some one to get that 700+, do they have to ace those subjects?
Quentin
Hi Quentin,
The simple answer to that is: No, that's not true. Sometimes Combinatorics and Probability show up at the high levels, but they're not the only categories that can appear at that level. Imagine if you were to become perfect at those categories, but you only saw a handful of questions from them on the GMAT... For practical purposes, emphasizing those two minor math categories during your studies is not a good use of your time. You should first put your emphasis into the "big" categories - the ones that lead to lots of points. To that end, how well do you perform on DS questions, algebra, arithmetic, number properties, geometry, math formula questions, etc.? Until you're great at those big categories, AND really good at Verbal too, then a 700+ won't be possible.
Overlapping Sets Questions in DS
Dear Rich,
I’m not sure how to handle these types of questions in Data Sufficiency. What is the logic?
How many directors of both Company K and Company R?
(1) Thee were 17 directors present at joint meeting of the directors of Company K and Company R, and no directors were absent.
(2) Company K has 12 directors and Company R has 8 directors."
Roberta
Hi Roberta,
This DS question is based on a variation of the "overlapping sets" concept that you'll likely see on the GMAT once or twice. There are several different ways to solve this problem, but since this is a simple variation, I'll show you the simple math.
The idea is this: If a person is a member of BOTH groups, then that person has been "counted" twice (once for the first group and once for the second). When calculating the total number of people, you're NOT supposed to count people twice, so you have to mathematically remove that "second count."
Here's a simple example:
3 people total
1 person in group A
1 person in group B
1 person in BOTH group A and B
Total in group A = 2
Total in group B = 2
But that DOES NOT mean that there are 4 people; there are only 3.
In this type of question, the "math" formula is Total = Group A + Group B - BOTH = 2 + 2 - 1 = 3 people total
The same logic applies in this question.
Total = 17
Company K = 12
Company R = 8
Both = ?
Total = CompK + CompR - BOTH
17 = 12 + 8 - BOTH
17 = 20 - BOTH
3 = BOTH
Getting Comfortable with DS Overall
Hi Rich,
I'm wondering whether the answers to the DS questions in the GMAT Exam will be of similar length and complexities as the one in the OG's or whether this is only for practice purposes. In reality, I'm doing not too bad on PS but DS is being a nightmare for me.
Seline
Hi Seline,
The 5 answer choices to DS questions are always the same 5 answers (and in that order). While the wording of the 5 answers might appear to be complex, each defines a specific set of results. Once you've done more practice and you're comfortable with the logic behind each of the 5 choices, then selecting the proper one will be a bit easier.
If you're referring to the explanations behind each of the DS questions in the OG, then it's worth noting that sometimes the "math" approach to solving a problem can be quite complicated. DS questions offer a certain degree of flexibility to the Test Taker though; sometimes the easiest way to correctly solve a DS question is to prove that a pattern exists in the data (by TESTing Values or knowing Number Properties, for example).
Keep practicing though and make sure that you take lots of notes when you do your work. This will help you to hone your skills before Test Day.
GMAT assassins aren't born, they're made,
Rich
