If b ≠ 0 and a > b, is a > c?
(1) a/b> c/b
(2) 5ab > 6bc
From a cursory glance, you can see that GMAT math takes you back to concepts that you learned in high school. Look a bit closer and you see that it actually takes you back much further than that, to math you learned in elementary school – integers, positives/negatives, etc. One of the interesting things about the GMAT is that sometimes these throwbacks to simple math are used to create challenging critical thinking problems. The problem above is one of those.
Post your answer and your method in the comments below. We’ll share the full Kaplan explanation, with secrets for how to master GMAT Data Sufficiency, in tomorrow’s blog entry.
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
One of the most important techniques to solving algebra problems, on the GMAT quantitative section or otherwise, is factoring. This technique, taking advantage of the “distributive property” of multiplication, lets you pull a common factor outside of a sum of terms, or to distribute it across those terms. In other words:
2x + 2y + 2z ↔ 2(x + y + z)
But did you know that the distributive property applies to grammar?
Well, not literally. But for quant experts confused by Parallelism in Sentence Correction, it can be helpful to imagine it as a distribution problem. When a sentence has a list of items, auxiliary verbs such as the “had” in “had been,” and prepositions such as “by” and “in,” can be “distributed” or “factored” across the list.
…by name, by date, or by subject ↔ …by (name, date, or subject)
Of … 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
We’ve already covered modifiers in GMAT sentence correction several times before. But, as one of the most common question types on the verbal section, and one of the types that requires the most finesse, there is still more to cover!
Today, I want to address a common misconception. Generally, modifiers must be placed as close as possible to the thing they modify. However, students sometimes mistake “as close as possible” for “adjacent.” Many test-takers find themselves confused when a long string of nouns, often peppered with prepositions, precedes a modifier. But as long as the modifier can be unambiguously linked to a specific part of that phrase, the sentence is grammatically correct. To illustrate, look at the following sentence, which is correct as written:
The members of parliament who attended the conference were pleased with the lush accommodations they received.
The modifier is the phrase “who attended the conference,” … 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 … Read full post
As anyone who has spent any time on GMAT Sentence Correction can tell you, the English language is complex. SC problems will frequently test idioms and tricky verb tenses, among other things. But despite a few exceptions (do you know the difference between economic and economical?), subtle shifts in the meanings of similar words aren’t usually tested in GMAT sentences. They are, however, tested on Critical Reasoning and Analytical Writing prompts.
Assumptions on the GMAT occur when the scope of discussion shifts between the evidence and the conclusion. In an earlier article, I discussed a stimulus involving burgers. One such “scope shift” in that article was that the evidence discussed cholesterol, while the conclusion discussed health in general; another involved evidence about a price reduction and a conclusion about increased consumption of burgers. Some of these are easier to spot than others, but all of them involve looking for … Read full post
The key to many GMAT coordinate geometry questions is to remember that coordinate geometry is just another way of expressing the possible solutions to a two variable equation. Each point on the line in a coordinate plane corresponds to a solution for the equation of that line.
The base equation for a line is y = mx + b, where b is the y intercept, or the point at which the line crosses the y-axis, and m is the slope, or the steepness of the line. More specifically, the slope of a line is the change in the y coordinates divided by the change in the x coordinates between any two points on the line.
While understanding the basic format for an equation of a line can be very useful on the GMAT quantitative section, you will encounter GMAT problems in which it is faster and easier to think … Read full post