One of the hallmark points of confusion on GMAT Data Sufficiency is the dreaded Yes/No question.
In a Value question, such as “What is the value of x?” the question of sufficiency is a familiar one: if you can solve for x, you have sufficiency. But in a Yes/No question, especially when variables are involved, finding a solid answer can be a much cloudier process.
Sample GMAT Data Sufficiency Yes/No Question
The best way to clear this fog is with a concrete example. Let’s look at this Data Sufficiency question, along with its first statement:
Is x positive?
(1) x^2 > 1
Is Statement (1) sufficient to answer the question? Unless you have a comprehensive understanding of the underlying Number Properties at work here, your first reaction to this statement is likely to try out different numerical values for x, because working with real numbers instead of variables will … Read full post
Yesterday, we posted a GMAT practice question on Facebook. It got a lot of attention and many responses. Here it is again:
Our Facebook audience mostly answered A, with a few votes for D. The correct answer is indeed A, and here’s why…
- Statement (1) is exactly what is needed – it gives you a precise value for . Statement (1) is sufficient, so eliminate answer choices C and E.
- Statement (2) alone, however, leads to two possible values for b, because you’d have to substitute the square roots of 25 for a, and those square roots are BOTH positive AND negative 5 (remember this! The GMAT likes to
Did you try out our GMAT Data Sufficiency practice question? If not, take a couple minutes now to give it a try before reviewing the explanation.
Now, let’s get down to brass tacks on the Geometry and DS skills you need to solve this one…
One way to find the area of a quadrilateral is to divide it into triangles and add the areas of the triangles, which can be found using the formula for the area of a triangle: (1/2)(Base)(Height).
If you add dashed lines to the diagram connecting points A and C and points B and D, you will see that the quadrilateral is composed of 4 right triangles:
You can see that one side of each triangle is a radius of one of the circles; for example, AB is a radius of circle A and is the hypotenuse of triangle ABE. Also, you’ll notice that triangles … Read full post
This year, I’d like to learn to play chess. I imagine that I’m going to have to read some about chess, but mostly practice playing it a whole lot in order to learn the game. I suppose that I’m going to have to find a willing partner – someone who has the patience to play chess with a novice.
Here’s some good news for you: as you learn to “play” the GMAT, you have a willing partner – Kaplan. The best way to increase your score on the GMAT is to practice. Seems obvious, right? Well, it’s just like any skill you’re trying to acquire – the more you do it, the more comfortable you become with it, the more you understand the nuances, the ins and outs, and the closer you become to being an expert.
So, let’s play a practice round. No worries, this is a … Read full post
The Graduate Management Admission Test (GMAT) is probably unlike any test you’ve ever taken in your academic career. The GMAT is a computer-adaptive test designed to provide a common yardstick by which business school admissions committees can measure applicants and their ability to succeed in their M.B.A. programs.
The test consists of three sections and is scored on a range between 200 and 800.
Your GMAT Score
GMAT scores are used by business schools to provide a common yardstick to compare candidates for admission. On the GMAT, you will actually receive four scores:
- A total score, ranging from 200-800
- A math subscore, ranging from 0-60
- A verbal subscore, ranging from 0-60
- A score for your AWA, ranging from 0-6
- An Integrated Reasoning subscore, ranging from 1-8
Your Percentile Rank
Each of the above scores will be accompanied by a percentile rank. The percentile rank highlights what proportion of test takers … Read full post
On the GMAT, there is only one correct answer to each question (How many caught the Highlander reference in the title? Be honest!).
I know, big surprise, right?
But that simple, obvious statement leads us to a powerful deduction. Some Problem Solving questions on the Quantitative section will have terms, variables, or unknowns that are unsolvable—they could take multiple values on the basis of the information in the stem. And we’re not talking Data Sufficiency here. “Not sufficient” isn’t a choice (Occasionally, “Cannot be determined” is a choice on problem solving questions. This answer is usually a trap, but you can use Data Sufficiency solving techniques to see if multiple answers are possible). So if the answer choices are numbers or proportions, and some term in the question stem is unsolvable, that undetermined x-factor can’t affect the outcome. Some ratio or mathematical step in the solution has to … Read full post
In poetry, a rose is a rose is a rose. On GMAT problems with central angle “slices” in circles, a fraction is a fraction is a fraction.
This may seem like common sense. Cut a pizza into six slices. If you cut it evenly, each slice now has one-sixth the cheese, one sixth the crust, and an angle of one sixth the way around a circle—that is, 60 degrees. However, though this may seem obvious, it’s actually a very useful technique for resolving certain geometry problems.
Consider the following Data Sufficiency question:
In a radius 6 circle, two points A and B are connected to the center, point O. What is angle AOB?
1) The length of the minor arc defined by sector O is 1.5π
2) The area of the sector defined by angle AOB is 4.5π
One of the most common mistakes that I see students make when practicing for the GMAT is the misapplication of the rules that govern square roots. When approaching a question that involves radicals, it is vital that you know not only the rules that you must follow, but also the operations that are commonly believed to be rules, but are not. On test day, the wrong answer choices will almost always be derived from the latter.
If you need to manipulate a square root, you must remember two key rules. First, that √(ab) = √a x √b and, second, that the √(a/b) = √a/√b. For example, if you need to simplify √20, you can rewrite it as √(4×5). When choosing which factors to use, always look for perfect squares. Since 4×5 includes the perfect square 4, it is better than 2×10, which does not include a perfect … Read full post
The trickiest question type in the quantitative section of the GMAT for most students is yes/no data sufficiency questions. When approaching these problems, it is imperative that you keep in mind the purpose of data sufficiency.
Let’s start with a review of data sufficiency. On these questions, your goal is not to find the answer. Rather, it is to determine if you have enough information to find the answer, regardless of what the answer is. On value questions, this is fairly straightforward. If you are asked for the value of x and you know it is 4, that’s sufficient, but if it could be 4 or 6, that’s not sufficient. In the former case we could narrow down the possibilities to one answer. In the latter, we could not.
Now let’s see how this same concept applies to yes/no questions. If a question asks us if x is positive and … Read full post
It is essential to remember that the GMAT is about more than just doing the math correctly. The GMAT is really a test of your critical thinking abilities – that is, your ability to not just do the work, but to figure out exactly what that work is.
To that end, the GMAT will often present you with problems that would take too long to solve if you do all of the math that is possible. I have had countless students approach me to tell me that if they were not timed, they could solve all of the math questions. However, they just cannot find a way to complete the problems in time. Additionally, all the extra math provides opportunities for careless errors. I always tell these students the same thing – do only the math you absolutely need to in order to reach the correct answer.
This is especially … Read full post