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
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
The holidays are upon us, and with them come a flurry of seasonal activities: shopping trips, parties, and visits with family and friends. If you’re planning on taking your GMAT in January, you’re probably struggling with the challenge of fitting your studies into your holiday schedule. Here are a few tips to help you make the most of this busy time.
First, acknowledge your limitations. Because of your holiday obligations, you’ll probably need to scale back your GMAT study time. The holidays provide you with a great opportunity to recharge mentally and emotionally, so there’s nothing wrong with cutting back a little on your studies to give yourself some more personal time. You’ll be able to create a study schedule–and stick to it–if you’re realistic with yourself about how much time you’ll actually have for studying over the holidays.
Second, since you’ll have less time to study, plan out … Read full post
A few months ago I had a student in one of my GMAT classes tell me her study plan. She was very diligent and committed to the study process, and the plan was a very well thought out and detailed. Furthermore, she was executing the plan brilliantly. The problem was that her score was going nowhere. She wasn’t gaining any ground from her masterful execution. What was the problem?
After digging a bit deeper, one thing stood out. She was using all the tools: practice tests, online quizzes, workshops, workbooks etc. None of this seemed odd. In fact, it was all commendable. However, there was a fatal flaw in the way she was using these resources. She wanted to makes sure that she had the endurance to answer these questions on test day. Therefore, when she sat down to do quantitative problems, she would create a set of 37, do … Read full post
This task probably won’t be given to you directly in the question stem—more likely, this would be an intermediate step after translating a word problem or plugging in numbers for variables. But it’s certain you’ll see something like this at some point on some GMAT problem.
In real life, you might plug these straight into a calculator. Doing so would give us this:
Ugly, huh? A five-digit number divided by a three-digit number. But the result is a nice even 30. There must be a better way to get there if the division is so neat! The shortcut is to divide. Any time you have numbers over numbers, you should always cancel, cancel, cancel. Dividing first keeps your numbers small … Read full post
The Wrentham Village Premium Outlets are a great place to stop for cheap brand-name clothes, and they’re a popular tourist destination for visitors to Massachusetts. Like all tourist/retail locations, they need to get people in the door. They’ve tried lot of things, but their latest gimmick has interesting implications for GMAT students. They’ve started stacking discounts.
Nearly every store in the mall has signs that say something like, “65% off, PLUS take an additional 20% off!” Moreover, a coupon book gives additional discounts—the particular store with that sign also offered 15% off purchases over a certain value.
To the unenlightened, this seems too good to be true. After all, 65% + 20% + 15% = 100%. Are we seriously to believe that the outlet store is giving away things for free?
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
Take a look at the picture with this blog. It’s an iconic optical illusion. Stare at it—what do you see? The picture is called the Great Wave off Kanagawa, painted by Katsushika Hokusai, a Japanese artist famed for his brilliant compositions. This drawing is of a wave, of course, but do you see the other wave, the reverse wave in the sky?
This image utilizes negative space. You take the whole frame, the great big rectangle, you block out that actual image—and what remains is, in its own right, an interesting picture.
To find the area of the shaded region, we need to subtract the area of the smaller inner circle from the large outer circle—the difference is the area of the ring.
But the concept extends beyond … Read full post
Tackling some of the tougher GMAT probability questions efficiently relies on both steady practice and your ability to make two key decisions well. First, you will need to quickly and accurately assess the total number of possible outcomes (the denominator of your probability equation). Second, within a multitude of possible approaches, you will need to determine the most efficient route to calculate the number of desired outcomes (the numerator of your probability equation).
With the clock ticking away on your GMAT CAT, figuring out the total number of possibilities can be time-consuming and fraught with room for error. For instance, if a question asks about the probability of getting at least 2 heads on 5 coin tosses, you could sit there all day writing out possibilities:
So forth and so on. I know I got dizzy with the possibilities just writing those three out. There is … Read full post
Translating word problems into algebra is a staple skill of GMAT test-takers, one that underlies countless problems in practice and on Test Day. But some challenging translations occur as part of probability and combinatorics problems. That’s because a pair of the most basic words in the English language, “And” and “Or,” suddenly become overburdened with mathematical significance.
“And” is the simpler of the two. When “And” represents independent choices—cases in which one option or arrangement has no impact on the other choice—just multiply the outcomes. For instance:
“The number of ways to purchase three board games and two video games” is an independent choice. The board games we pick have no impact on the video games we pick. So, to translate: [The number of ways to purchase three board games] × [the number of ways to select two video games]. Of course, we’d need the combination formula … Read full post