GRE - Info NOT Content - Quantitative Reasoning Flashcards
Quant Reasoning assesses
basic mathematical skills
understanding of elementary mathematical concepts
ability to reason quantitatively and to model and solve problems with quantitative methods
Quant Reasoning - Some of the questions in the measure are posed in real-life settings, while others are posed in purely mathematical settings. The skills, concepts and abilities are tested in the four content areas below:
Arithmetic topics include properties and types of integers, such as divisibility, factorization, prime numbers, remainders and odd and even integers; arithmetic operations, exponents and roots; and concepts such as estimation, percent, ratio, rate, absolute value, the number line, decimal representation and sequences of numbers.
Algebra topics include operations with exponents; factoring and simplifying algebraic expressions; relations, functions, equations and inequalities; solving linear and quadratic equations and roots; solving simultaneous equations and inequalities; setting up equations to solve word problems; and coordinate geometry, including graphs of functions, equations and inequalities, intercepts and slopes of lines.
Geometry topics include parallel and perpendicular lines, circles, triangles — including isosceles, equilateral and 30°-60°-90° triangles — quadrilaterals, other polygons, congruent and similar figures, three-dimensional figures, area, perimeter, volume, the Pythagorean theorem and angle measurement in degrees. The ability to construct proofs is not tested.
Data analysis topics include basic descriptive statistics, such as mean, median, mode, range, standard deviation, interquartile range, quartiles and percentiles; interpretation of data in tables and graphs, such as line graphs, bar graphs, circle graphs, boxplots, scatterplots and frequency distributions; elementary probability, such as probabilities of compound events and independent events; random variables and probability distributions, including normal distributions; and counting methods, such as combinations, permutations and Venn diagrams. These topics are typically taught in high school algebra courses or introductory statistics courses. Inferential statistics is not tested.
there are some important assumptions about numbers and figures that are listed in the Quantitative Reasoning section directions:
All numbers used are real numbers.
All figures are assumed to lie in a plane unless otherwise indicated.
Geometric figures, such as lines, circles, triangles and quadrilaterals, are not necessarily drawn to scale. That is, you should not assume that quantities such as lengths and angle measures are as they appear in a figure. You should assume, however, that lines shown as straight are actually straight, points on a line are in the order shown, and more generally, all geometric objects are in the relative positions shown. For questions with geometric figures, you should base your answers on geometric reasoning, not on estimating or comparing quantities by sight or by measurement.
Coordinate systems, such as xy-planes and number lines, are drawn to scale; therefore, you can read, estimate or compare quantities in such figures by sight or by measurement.
Graphical data presentations, such as bar graphs, circle graphs and line graphs are drawn to scale; therefore, you can read, estimate or compare data values by sight or by measurement.
Quantitative Reasoning Question Types
The Quantitative Reasoning measure has four types of questions:
Quantitative Comparison Questions
Multiple-choice Questions — Select One Answer Choice
Multiple-choice Questions — Select One or More Answer Choices
Numeric Entry Questions
Each question appears either independently as a discrete question or as part of a set of questions called a Data Interpretation set. All of the questions in a Data Interpretation set are based on the same data presented in tables, graphs or other displays of data.
In the computer-based test, you are allowed to use a basic calculator — provided on-screen — on the Quantitative Reasoning measure. Read more about using the calculator.
Quantitative Comparison Questions
Description
Questions of this type ask you to compare two quantities – Quantity A and Quantity B – and then determine which of the following statements describes the comparison:
Quantity A is greater.
Quantity B is greater.
The two quantities are equal.
The relationship cannot be determined from the information given.
Quantitative Comparison Questions Tips for Answering
- Become familiar with the answer choices. Quantitative Comparison questions always have the same answer choices, so get to know them, especially the last choice, “The relationship cannot be determined from the information given.” Never select this last choice if it is clear that the values of the two quantities can be determined by computation. Also, if you determine that one quantity is greater than the other, make sure you carefully select the corresponding choice so as not to reverse the first two choices.
- Avoid unnecessary computations. Don’t waste time performing needless computations in order to compare the two quantities. Simplify, transform or estimate one or both of the given quantities only as much as is necessary to compare them.
- Remember that geometric figures are not necessarily drawn to scale. If any aspect of a given geometric figure is not fully determined, try to redraw the figure, keeping those aspects that are completely determined by the given information fixed but changing the aspects of the figure that are not determined. Examine the results. What variations are possible in the relative lengths of line segments or measures of angles?
- Plug in numbers. If one or both of the quantities are algebraic expressions, you can substitute easy numbers for the variables and compare the resulting quantities in your analysis. Consider all kinds of appropriate numbers before you give an answer: e.g., zero, positive and negative numbers, small and large numbers, fractions and decimals. If you see that Quantity A is greater than Quantity B in one case and Quantity B is greater than Quantity A in another case, choose “The relationship cannot be determined from the information given.”
- Simplify the comparison. If both quantities are algebraic or arithmetic expressions and you cannot easily see a relationship between them, you can try to simplify the comparison. Try a step-by-step simplification that is similar to the steps involved when you solve the equation 5=4x + 3 for x, or that is similar to the steps involved when you determine that the inequality
3y + 2
——— ), less than (
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
A symbol that appears more than once in a question has the same meaning throughout the question.
- Quantity A
The least prime number greater than 24
Quantity B
The greatest prime number less than 28
(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.
Explanation
For the integers greater than 24, note that 25, 26, 27, and 28 are not prime numbers, but 29 is a prime number, as are 31 and many other greater integers. Thus, 29 is the least prime number greater than 24, and Quantity A is 29. For the integers less than 28, note that 27, 26, 25, and 24 are not prime numbers, but 23 is a prime number, as are 19 and several other lesser integers. Thus, 23 is the greatest prime number less than 28, and Quantity B is 23. Thus, the correct answer is Choice A, Quantity A is greater.
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
A symbol that appears more than once in a question has the same meaning throughout the question.
- Lionel is younger than Maria.
Quantity A
Twice Lionel’s age
Quantity B
Maria’s age
(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.
Explanation
If Lionel’s age is 6 years and Maria’s age is 10 years, then Quantity A is greater, but if Lionel’s age is 4 years and Maria’s age is 10 years, then Quantity B is greater. Thus, the relationship cannot be determined. The correct answer is Choice D, the relationship cannot be determined from the information given.
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
- Quantity A
54% of 360
Quantity B
150
(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.
Explanation
Without doing the exact computation, you can see that 54 percent of 360 is greater than of 360, which is 180, and 180 is greater than Quantity B, 150. Thus, the correct answer is Choice A, Quantity A is greater.
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
INSERT FIGURE 1 FROM DESKTOP
4.Quantity A
PS
Quantity B SR (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.
Explanation
From Figure 1, you know that PQR is a triangle and that point S is between points P and R, so PS
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
- y = 2x⌃2 + 7x - 3
Quantity A is x and Quantity B is y
(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.
Explanation
If x=0 then y=2(0⌃2) + 7(0) - 3= -3, so in this case, x > y; but if x = 1, then y = 2(1⌃2) + 7(1) - 3 = 6 so in that case,
y > x. Thus, the correct answer is Choice D, the relationship cannot be determined from the information given.
Note that plugging numbers into expressions may not be conclusive. However, it is conclusive if you get different results after plugging in different numbers: the conclusion is that the relationship cannot be determined from the information given. It is also conclusive if there are only a small number of possible numbers to plug in and all of them yield the same result, say, that Quantity B is greater.
Now suppose there are an infinite number of possible numbers to plug in. If you plug many of them in and each time the result is, for example, that Quantity A is greater, you still cannot conclude that Quantity A is greater for every possible number that could be plugged in. Further analysis would be necessary and should focus on whether Quantity A is greater for all possible numbers or whether there are numbers for which Quantity A is not greater.
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
- The following sample questions focus on simplifying the comparison.
y > 4
Quantity A:
3y + 2
————
5
Quantity B: y (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.
Explanation
Set up the initial comparison:
3y + 2
———— is ? to y (, or =)
5
Then simplify:
Step 1: Multiply both sides by 5 to get 3y + 2 ? 5y
Step 2: Subtract 3y from both sides to get 2 ? 2y
Step 3: Divide both sides by 2 to get 1 ? y
The comparison is now simplified as much as possible. In order to compare 1 and y, note that you are given the information y > 4 (above Quantities A and B). It follows from y > 4 that y > 1 or so that in the comparison 1 ? y, the placeholder ? represents less than ( -y. So the relationship in the final, simplified inequality may be the opposite of the relationship between Quantities A and B. This is another reason to consider the impact of each step carefully.
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
- Quantity A
2⌃30 - 2⌃29
—————————
2
Quantity B
2⌃ 28
(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
Explanation
Set up the initial comparison:
2⌃30 - 2⌃29
———————— ? 2⌃28
2
Then simplify:
Step 1: Multiply both sides by 2 to get 2⌃30 - 2⌃29 ? 2⌃29
Step 2: Add 2⌃29 to both sides to get 2⌃30 ? 2⌃29 + 2⌃29
Step 3: Simplify the right-hand side using the fact that (2)(2⌃29) = 2⌃30 to get 2⌃30 ? 2⌃30
The resulting relationship is equal to (=). In reverse order, each simplification step implies equal to in the preceding comparison. So Quantities A and B are also equal. Thus, the correct answer is Choice C, the two quantities are equal.
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
- Quantity A
x⌃2 + 1
Quantity B
2x - 1
(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.
Explanation
Set up the initial comparison:
x⌃2 + 1 ? 2x - 1
Then simplify by noting that the quadratic polynomial
x⌃2 - 2x + 1 can be factored:
Step 1: Subtract 2x from both sides to get x⌃2 - 2x + 1 ? -1
Step 2: Factor the left-hand side to get (x - 1)⌃2 ? -1
The left-hand side of the comparison is the square of a number. Since the square of a number is always greater than or equal to 0, and 0 is greater than the simplified comparison is the inequality (x-1)⌃2 > -1 and the resulting relationship is greater than (>). In reverse order, each simplification step implies the inequality greater than (>) in the preceding comparison. Therefore, Quantity A is greater than Quantity B. The correct answer is Choice A, Quantity A is greater.
Quantitative Comparison Questions
Sample Questions
Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given, and select one of the following four answer choices:
(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.
- w > 1
Quantity A
7w - 4
Quantity B
2w + 5
(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.
Explanation
Set up the initial comparison:
7w - 4 ? 2w + 5
Then simplify:
Step 1: Subtract 2w from both sides and add 4 to both sides to get 5w ? 9
Step 2: Divide both sides by 5 to get w ? 9 ( or 9/5)
—
5
The comparison cannot be simplified any further. Although you are given that w > 1 you still don’t know how w compares to 9/5 or 1.8. For example, if w=1.5 then w1.8 In other words, the relationship between w and 9/5 cannot be determined. Note that each of these simplification steps is reversible, so in reverse order, each simplification step implies that the relationship cannot be determined in the preceding comparison. Thus, the relationship between Quantities A and B cannot be determined. The correct answer is Choice D, the relationship cannot be determined from the information given.
The strategy of simplifying the comparison works most efficiently when you note that a simplification step is reversible while actually taking the step. Here are some common steps that are always reversible:
Adding any number or expression to both sides of a comparison
Subtracting any number or expression from both sides
Multiplying both sides by any nonzero number or expression
Dividing both sides by any nonzero number or expression
Remember that if the relationship is an inequality, multiplying or dividing both sides by any negative number or expression will yield the opposite inequality. Be aware that some common operations like squaring both sides are generally not reversible and may require further analysis using other information given in the question in order to justify reversing such steps.
Strategies of simplifying the comparison that are reversible
The strategy of simplifying the comparison works most efficiently when you note that a simplification step is reversible while actually taking the step. Here are some common steps that are always reversible:
Adding any number or expression to both sides of a comparison
Subtracting any number or expression from both sides
Multiplying both sides by any nonzero number or expression
Dividing both sides by any nonzero number or expression
Remember that if the relationship is an inequality, multiplying or dividing both sides by any negative number or expression will yield the opposite inequality. Be aware that some common operations like squaring both sides are generally not reversible and may require further analysis using other information given in the question in order to justify reversing such steps.
Multiple-choice Questions — Select One Answer Choice
Description
These questions are multiple-choice questions that ask you to select only one answer choice from a list of five choices.
Tips for Answering
Tips for Answering
Use the fact that the answer is there. If your answer is not one of the five answer choices given, you should assume that your answer is incorrect and do the following:
Reread the question carefully – you may have missed an important detail or misinterpreted some information.
Check your computations – you may have made a mistake, such as mis-keying a number on the calculator.
Reevaluate your solution method – you may have a flaw in your reasoning.
Examine the answer choices. In some questions you are asked explicitly which of the choices has a certain property. You may have to consider each choice separately or you may be able to see a relationship between the choices that will help you find the answer more quickly. In other questions, it may be helpful to work backward from the choices, say, by substituting the choices in an equation or inequality to see which one works. However, be careful, as that method may take more time than using reasoning.
For questions that require approximations, scan the answer choices to see how close an approximation is needed. In other questions, too, it may be helpful to scan the choices briefly before solving the problem to get a better sense of what the question is asking. If computations are involved in the solution, it may be necessary to carry out all computations exactly and round only your final answer in order to get the required degree of accuracy. In other questions, you may find that estimation is sufficient and will help you avoid spending time on long computations.
Sample quest 1
If 5x + 32 = 4 - 2x what is the value of x ?
(A) -4 (B) -3 (C) 4 (D) 7 (E) 12
Explanation
Solving the equation for x, you get 7x = 28 and so x = -4. The correct answer is Choice A, -4.
Sample Ques 2
Which of the following numbers is farthest from the number 1 on the number line?
(A) -10 (B) -5 (C) 0 (D) 5 (E) 10
Explanation
Circling each of the answer choices in a sketch of the number line (Figure 4) shows that of the given numbers, -10 is the greatest distance from 1.
INSERT FIG 4 NUM LINE PIC
Another way to answer the question is to remember that the distance between two numbers on the number line is equal to the absolute value of the difference of the two numbers. For example, the distance between -10 and 1 is |-10 - 1| = 11 and the distance between 10 and 1 is |10 - 1| = |9| = 9 The correct answer is Choice A, -10.
SAMPLE QUES 3
INSERT FIG 5
The figure above shows the graph of a function f defined by f(x) = |2x| + 4 for all numbers x. For which of the following functions g, defined for all numbers x, does the graph of g intersect the graph of f ?
(A) g(x) = x-2 (B) g(x) = x+3 (C) g(x) = 2x-2 (D) g(x) = 2x + 3 (E) g(x) = 3x - 2
Explanation
You can see that all five choices are linear functions whose graphs are lines with various slopes and y-intercepts. The graph of Choice A is a line with slope 1 and y-intercept shown in Figure 6.
INSERT FIG 6 HERE
It is clear that this line will not intersect the graph of f to the left of the y-axis. To the right of the y-axis, the graph of f is a line with slope 2, which is greater than slope 1. Consequently, as the value of x increases, the value of y increases faster for f than for g, and therefore the graphs do not intersect to the right of the y-axis. Choice B is similarly ruled out. Note that if the y-intercept of either of the lines in Choices A and B were greater than or equal to 4 instead of less than 4, they would intersect the graph of f.
Choices C and D are lines with slope 2 and y-intercepts less than 4. Hence, they are parallel to the graph of f (to the right of the y-axis) and therefore will not intersect it. Any line with a slope greater than 2 and a y-intercept less than 4, like the line in Choice E, will intersect the graph of f (to the right of the y-axis). The correct answer is Choice E, g(x) = 3x - 2
Sample Ques 4
A car got 33 miles per gallon using gasoline that cost $2.95 per gallon. Approximately what was the cost, in dollars, of the gasoline used in driving the car 350 miles?
(A) $10 (B) $20 (C) $30 (D) $40 (E) $50
Explanation
Scanning the answer choices indicates that you can do at least some estimation and still answer confidently. The car used 350/33 gallons of gasoline, so the cost was
(350/33)(2.95) dollars. You can estimate the product (350/33)(2.95) by estimating 350/33 a little low, 10, and estimating 2.95 a little high, 3, to get approximately (10)(3) = 30 dollars. You can also use the calculator to compute a more exact answer and then round the answer to the nearest 10 dollars, as suggested by the answer choices. The calculator yields the decimal 31.287…, which rounds to 30 dollars. Thus, the correct answer is Choice C, $30.
Sample Ques 5
A certain jar contains 60 jelly beans — 22 white, 18 green, 11 yellow, 5 red and 4 purple. If a jelly bean is to be chosen at random, what is the probability that the jelly bean will be neither red nor purple?
(A) 0.09 (B) 0.15 (C) 0.54 (D) 0.85 (E) 0.91
Explanation
Since there are 5 red and 4 purple jelly beans in the jar, there are 51 that are neither red nor purple, and the probability of selecting one of these is 51/60. Since all of the answer choices are decimals, you must convert the fraction to its decimal equivalent, 0.85. Thus, the correct answer is Choice D, 0.85.
Description
These questions are multiple-choice questions that ask you to select one or more answer choices from a list of choices. A question may or may not specify the number of choices to select.
Tips for Answering
Tips for Answering
Note whether you are asked to indicate a specific number of answer choices or all choices that apply. In the latter case, be sure to consider all of the choices, determine which ones are correct, and select all of those and only those choices. Note that there may be only one correct choice.
In some questions that involve conditions that limit the possible values of numerical answer choices, it may be efficient to determine the least and/or the greatest possible value. Knowing the least and/or greatest possible value may enable you to quickly determine all of the choices that are correct.
Avoid lengthy calculations by recognizing and continuing numerical patterns.
Sample Questions
Directions: Select one or more answer choices according to the specific question directions.
If the question does not specify how many answer choices to select, select all that apply.
The correct answer may be just one of the choices or as many as all of the choices, depending on the question.
No credit is given unless you select all of the correct choices and no others.
If the question specifies how many answer choices to select, select exactly that number of choices.
SQ 1
Which two of the following numbers have a product that is between -1 and 0 ?
Indicate both of the numbers.
(A) -20
(B) -10
(C) 2⌃-4
(D) 3⌃-2
Explanation
For this question, you must select a pair of answer choices. The product of the pair must be negative, so the possible products are
(-20)(2⌃-4), (-20)(3⌃-2), (-10)(2⌃-4), and (-10)(3⌃-2). The product must also be greater than -1. The first product is -20/2⌃4 = -20/16 -1, so you can stop there. The correct answer consists of Choices B (-10 ) and C ( 2-4).