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How to Find Area on the GRE

By vivian kerr posted February 6, 2012

Need better scores in Geometry questions on the GRE? Keep this guide handy while you study online for the GRE. These formulas are essential to answer questions about Area on Test Day.

Triangles - To find the area of a triangle, we use the formula A = ½ bh, where b = base and h = height. The base and the height of the triangle must always form a 90 degree angle. Keep in mind that the height can be inside or outside the triangle.

Quadrilaterals - To find the area of a square, we use the formula A = s², where s = side of the square. To find the area of a rectangle, we use the formula A = lw, where l = length and w = width.

To find the area of a parallelogram, we use the formula A = bh, where b = base and h = height. We do NOT multiply the two side lengths. Remember the base and the height must be perpendicular.

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GRE Quant Numeric Entry: An old friend

By oren weinrib posted January 30, 2012

The new GRE Quantitative section introduces some minor twists and turns to the familiar test-taking landscape, but the content is the same basic high-school math: primarily arithmetic, algebra, geometry, simple statistics and data analysis, with a smattering of topics like probability and permutations/combinations. The good news is that you’ve probably been prepping for this kind of math since you took the ACT/SAT or other standardized tests years ago.

In this blog, we’ll examine the numerical entry question type. It may be new to the GRE, but other than a couple of technical details, this material is old hat. You’ve been doing this kind of math problem as homework since you were in grade school. You’re given a question, you compute the answer, and instead of writing it on paper, you type it into a box on the screen.

Need some GRE practice? Try this GRE numeric entry question and test your skills!

Because your answer is computer-scored and there are no answer choices to guide you, be careful to give the answer in the units requested, such as meters vs. kilometers or thousands vs. millions. Note if you’re being asked for a decimal or a percent, or to fill in a fraction. Some questions may ask you to round, for instance to the nearest .1 percent. In this case, don’t round any intermediate calculations, only your final calculated answer. That is to say, if you are doing a problem with the calculator that asks for a decimal , use the raw calculations from step to step. If you did the same problem using fractions, you could use the calculator to convert your answer at the end. When using the “Transfer Display” feature from the calculator, you may need to edit the answer to the required degree of precision. You can’t click and highlight, so use the Backspace key.

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GRE Quant MC – Single Blank: To Calculate or not to Calculate?

By oren weinrib posted January 25, 2012

The new GRE Quantitative section adds a bit of complexity to the testing methodology by changing up the way you are asked to provide answers. In addition to the comparison task and the standard multiple choice questions that appeared on the previous GRE format, the new question types include the “Select one or more” and the “Numeric entry” questions. The other novelty is the use of the on-screen calculator. In this blog entry, we’ll look at the traditional single answer multiple choice question in the context of the calculator.

Judicious use of the calculator will aid your performance on the test. One feature of the single answer multiple choice is that the answer choices can provide valuable information about the degree of precision required. Unlike the “Numeric entry” questions which require an exact answer, this type may yield to a quick estimate that saves you both time and the possibility of calculation errors.

Try this GRE quantitative practice problem and test your math skills today!

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5 Tips for Solving Tough GRE Algebra Questions

By vivian kerr posted January 24, 2012

Looking to jump-start your Quantitative scores on the GRE? Here are five tips that are almost guaranteed to appear on Test Day. Watch out for them on your solo adaptive practice games on Grockit!

1. For n equations, you need n variables to solve. The GRE will often present you with two or more equations with multiple variables. If there are 2 variables in an equation (for example, x and y), then there must be 2 equations that each contain those variables in order to solve. The two common ways to solve are Substitution and Combination.

2. Substitute carefully for Functions. It’s helpful to think of (x, f(x)) as another way of writing (x, y). For many function questions, you can Pick Numbers or Substitute for the variables to solve! For example, if a question provides a Function such as f(x) = 3x + 2, and wants to know what f(x – 1) is when x = 3, first rewrite the function, substituting x – 1 in for x. We would get: f(x – 1) = 3(x – 1) + 2, or f(x – 1) = 3x – 3 + 2. That becomes f(x – 1) = 3x – 1. Now the question asks what f(x – 1) will be when x = 3. Substitute in x = 3 to solve. f(x – 1) = 3(3) – 1 becomes f(x – 1) = 9 – 1. The answer is f(x – 1) = 8.

3. Know your number properties. The GRE tests number properties heavily, and you must be comfortable with words like integers, rational numbers, primes, etc. The properties of odds and evens, integers, fractions, positives, and negatives will all appear in various questions on your GMAT test as well. Don’t ever make assumptions about unknown variables. Unless you are told otherwise by the limitations in the question, variables can be negative integers, negative fractions, zero, positive fractions, or positive integer. You may need to Pick Numbers from multiple categories, especially for Quantitative Comparisons questions.

4. Flip the inequality when you multiply or divide by a negative number. Remember that when you multiply or divide by a negative number, you must reverse the direction of the inequality. The non-flipped version will almost always be one of the wrong answer choices (of course!).

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Two Types of Averages on the GRE: Mean and Rates

By vivian kerr posted January 21, 2012

The word “average” on the GRE can refer to two concepts: arithmetic mean, and the average speed (or average rate) formula. It’s important not to confuse the two on the Test Day, as they require different formulas to solve.

Mean is the mathematical average. This is defined as the sum of the terms divided by the number of terms. Mean = Sum / # of terms. For a list of consecutive integers or evenly spaced numbers, the mean is equal to the median, or the middle number. For example, the “average” of 3, 5, and 9 is 5.67.

Test your skills with this GRE rate and work practice question.

Average Speed or Average Rate is often found in complex word problems. This type of question is one many students are less familiar with so you may not have seen it before. Let’s review two important equations to remember and look at how this concept appears on the GRE.

The first formula to memorize is: D = R x T. This stands for Distance = Rate x Time (referred to as the “DIRT” formula). It is perfectly acceptable to also think of it as Time = Distance / Rate or as Rate = Distance / Time as well. Usually the “Rate” is speed but it could be anything “per” anything. In a word problem, if you see the word “per” you know this is a question involving rates.

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Dealing with Quadratics on the GRE

By vivian kerr posted January 18, 2012

Quadratics are common to GRE algebra, and knowing how to Factor and FOIL are necessary skills that will be required on Test Day, especially for Multiple Choice questions.

How to Foil: Sometimes you will be presented with two factors: (x – 1)(x + 4), for example. How can you turn this into a quadratic? Simply multiply the First two terms, the Outer two terms, the Middle two terms, and the Last two terms. This will look like: x*x + 4*x -1*x -1*4. That simplifies to x^2 + 4x – x – 4, or x^2 + 3x – 4. This three-termed expressions is called a quadratic equation.

How to Factor: The quadratic equation is a special polynomial. It has three terms and is in the form ax² + bx + c. The first term will always be squared, the middle term will always have the same variable, and the last term will contain only an integer. An example of a quadratic is x² – 5x + 6. To find the factors of this equation, we must set up our set of two parentheses: ( )( )

Need more algebra practice? Check out this practice question and see which strategy works best for you!

The first term in both parentheses must be x, since x multiplied by x is the only way to get x². Then we look at the coefficient of the second term, -5. It’s important to include the sign in front of the integer as part of the coefficient. One of the rules of quadratic equations is that the second terms in the two factors must add together to equal the middle term’s coefficient. So we need to think of two numbers that add together to give us -5. Another rule of quadratic equations is that the third term of the quadratic equation will equal the product of the second terms in the two factors. So not only do we need the two numbers to add together to equal -5, but we need them to multiply together to equal + 6. Therefore the factors must be: (x – 2) (x – 3). Therefore the “roots” or “solutions” to this quadratic are 2 and 3.

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The Revised GRE Quantitative: What to Expect

By jill muttera posted January 17, 2012

The Quantitative Reasoning sections of the GRE test your basic math skills, knowledge of mathematical concepts, and your ability to reason logically. You will not bring a calculator the the computer-based GRE. An on-screen calculator will be provided. Here’s all the basics you need to know to get started with your Quantitative GRE studying!

Timing: There are 2-3 sections of Quantitative Reasoning on the GRE, depending if the extra unscored section is Quantitative or Verbal. You will be given 35 minutes to answer approximately 20 questions per section. You will be able to answer some questions very quickly, while others will take more of your time. Time yourself with practice sections to see if you need to adjust your pacing.

Check out this GRE algebra practice question and test your skills on Grockit today!

Format: There are four types of questions on the Quantitative Reasoning sections. Let’s take a look at the four types.

-Quantitative Comparison: For these questions, you will be given two quantities in two different columns, Quantity A and Quantity B. After comparing the two quantities, you will be asked to determine if:

a) Quantity A is greater.

b) Quantity B is greater.

c) The two quantities are equal

d) The relationship cannot be determined from the information given.

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3 Steps for Data Interpretation on the GRE

By vivian kerr posted January 16, 2012

Been staring blankly at the tables, graphs, and charts that make up the Data Interpretation questions on the GRE? Here are three quick tips to keep you focused on this question-type, and allow you to more fully extrapolate the information presented in the data.

1. Read the labels first. Mentally categorize each graph, chart and table. Do not just skip the statistics entirely and go straight to the question! While you may think this will save you time, it actually significantly decreases your accuracy. Make sure you read every tiny piece of writing on or near the data, including titles, the labels for the x and y-axes, column names, and even footnotes. Scroll down to make sure you’ve caught everything.

2. Pay close attention to the units. Once you understand the labels, take special care to note the units (mph, m/sec, cm², etc.). Are we dealing with seconds, minutes, or hours? Does one graph represent the month of June, while the other graph represents the entire year? The units may change from graph-to-graph or chart-to-table. Especially note any given information about percentages, as Data Interpretation questions frequently require you to work with percents and raw numbers. Quickly note the relationship between the variables in each table, chart, or graph. Do they have a direct or indirect correlation? Where does the data spike or significantly decrease?

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The Need-to-Know Coordinate Geometry Basics Tested on the GRE

By vivian kerr posted January 6, 2012

It’s common for Quant students to be stronger in either algebra or geometry, so if it’s been awhile since you worked on Geometry questions, you might want to start with an overview of Plane Geometry basics here. If you’re confident with your lines, angles, and shapes, it’s time to move on to the most commonly tested GRE Coordinate Geometry concepts. Here are the need-to-know basics:

There are two main equations for straight lines. One form looks like: ax+by+c=0
For an equation that looks like this the slope is -a/b and the y intercept is -c/b .

For example, in the equation 2x + 3y + 6 = 0, the slope is -2/3 and the y-intercept is -2. The second equation is called slope-intercept form and looks like: y=mx+b. Here m is the slope and b is the y-intercept.