For questions relevant to the general or subject-specific Graduate Record Examination, abbreviated GRE.

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GRE Quantitative problem on distributions

I was doing some problems on this .Can some one please help me with the following: Here the given answer is that quantity B is grater than Quantity A. How is this obtained? Do we know anything ...
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0answers
14 views

Which version of Stewart for GRE Math?

I am planning on taking the GRE Math Exam and wanted to know which version of Stewart Calculus is useful for this exam as there are many versions of the book.
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17 views

GRE Math Subject Study Methods

I am a computer science major and have taken calculus 1,2,3 courses a while back. To be honest, I do not remember much from my math courses and have not applied them to any of my recent computer ...
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1answer
53 views

Determining a multiple of a power of 2.

I am thinking about this question which I believe is a possible GRE question. "Which of the following numbers is exactly divisible by 32? A) $1.9 \times 10^5 $ B) $1.9 \times 10^6$ C) $1.9 \times ...
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3answers
52 views

Convolution of sine and cosine.

So I came across this question while studying for the GRE Subject Exam, and I am not really sure how I am supposed to handle it. Let $$ f(x) = \int _0 ^{\pi} \sin t \cos (x+t) dt $$ I am to find where ...
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1answer
58 views

If $a,b>0$, find $\int_0^\infty \frac{e^{ax}-e^{bx}}{(1+e^{ax})(1+e^{bx})}dx$

The question is to find $$\int_0^\infty \frac{e^{ax}-e^{bx}}{(1+e^{ax})(1+e^{bx})}dx$$ where $a$ and $b$ are positive values. My attempt was to break this up into the sum $$ \int_0^\infty ...
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1answer
52 views

Substitution for Trig Integral - GRE Math Subject Test

Problem Statement: What is the value of $\int_{-\pi/4}^{\pi/4}(\cos t +\sqrt{1+t^{2}}\sin^{3}t\cos^{3}t)dt?$ I am working on an old GRE Math Subject test, and I am having trouble determining ...
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4answers
89 views

Among the following, which is closest to $\sqrt{0.016}$?

Among the following, which is closest in value to $\sqrt{0.016}$? A. $0.4$ B. $0.04$ C. $0.2$ D. $0.02$ E. $0.13$ My Approach: $(\frac{16}{1000})^\frac{1}{2} = (\frac{4}{250})^\frac{1}{2} = ...
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35 views

Maximum area of inscribed square

This is follow-on from Minimum area of Inscribed Square If I have square S with perimeter 40, i.e. each side 10, and I have inscribed square T, what is the Maximum area of T? How do I even go about ...
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63 views

Minimum area of Inscribed Square

GRE study guide asks The perimeter of square S is 40. Square T is inscribed in square S. What is the least possible area of square T? Choices are 45 48 49 50 52 They say answer is 50. How ...
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1answer
34 views

Equivalence of Repeating Decimal

GRE exam question asks what is greater $.\overline{717}$ or $.\overline{71}$ I believe both are equal, but GRE says that $.\overline{717}$ is greater. But why? If they repeat for infinity, isn't ...
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3answers
130 views

GRE Algebra answer is wrong

GRE study guide has following A developer has land that has $x$ feet of lake frontage. The land is to be subdivided into lots, each of which is to have either 80 feet or 100 feet of lake ...
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1answer
57 views

Three GRE Questions [closed]

I am currently studying for the GRE exam and there are two particular questions I am unable to solved. Help with them would be much appreciated. The first: k = 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + ...
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1answer
32 views

Normal Distribution, percent less than mean minus one std. dev

GRE Question, part b. My answer is 16%, but the book says 15%. Why? mean = 65 cm stdev = 5 cm Probability that penguin chosen at random will be less than 60 cm is 16%, it shows in Normal ...
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3answers
170 views

A and B are mutually exclusive, C and D are independent

Another GRE study question Let A, B, C, and D be events for which P(A or B) = 0.6, P(A) = 0.2, P(C or D) = 0.6,and P(C) = 0.5. The events A and B are mutually exclusive, and the events C and D ...
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3answers
714 views

Probability of choosing positive 2-digit integer with 4 in either place

GRE study exam guide has following If an integer is randomly selected from all positive 2-digit integers, what is the probability that the integer chosen has at least one 4 in the tens place ...
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2answers
80 views

Standard Deviation vs Population Standard Deviation

In GRE study guide, it gives difference between standard deviation and sample or population standard deviation. I understand the mechanics of this, i.e. in standard deviation you divide all ...
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2answers
22 views

Find Area of Similar Right Triangle

Need help to approach following from GRE study guide Here is what I have so far $area = 1/2 bh$ $area CDE = 1/2 bh = 42 = 21 bh$ $AD = 3CD$ Honestly, I'm not sure how to approach. Please give ...
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2answers
93 views

Derive quadratic formula [duplicate]

I cannot understand how quadratic formula to solve for $x$ was derived. On this website, it explains the steps Following I understand but I cannot understand how they got $b/2a$ and why they ...
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2answers
29 views

Given Function, find domain and description of graph $y = f(x)$

I am studying for Graduate Record Exam. The following question is difficult. Given the domain and description of $f(x) = 5 - (x + 20)^2$, including its shape, and the $x$ and $y$-intercepts To find ...
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1answer
21 views

Determine the order relation between $x$ and $y$, given $5x-2y =2y-3x $

Given: $5x-2y =2y-3x $ $$ \begin{aligned} \text{Quantity A} && \text{Quantity B} \\ x && y \end{aligned}$$ $\bigcirc $ Quantity A is bigger ...
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1answer
16 views

n where it gives certain remainder for certain number

I am studying for GRE and need help with following question When the positive integer n is divided by 3, the remainder is 2 and when n is divided by 5, the remainder is 1. What is the least ...
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2answers
161 views

Wording and answer of algebra for GRE

I am studying for GRE and have been stumped by The question The answer Question: When the positive integer n is divided by 45, the remainder is 18. Which of the following must be a divisor of n? ...
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2answers
50 views

GRE. Rate problem and weighted average isn't intuitive.

Shaundra drove the same route to work each morning, Monday through Friday, in a particular week. On Monday and Tuesday she averaged 20 miles per hour, and on her three remaining work days she ...
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2answers
137 views

The possible remainders when a multiple of 4 is divided by 6, and when a multiple of 2 is divided by 3

I'm currently studying for the GRE and a specific type of question has me stumped. I have a two part question, but first here is one problem and my work: "If x is the remainder when a multiple of 4 ...
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3answers
71 views

GRE problem involving LCD, prime factorization, and sets.

I think this problem was a bit tricky and I'm trying to better think through this. Here is the problem: Let S be the set of all positive integers n such that $n^2$ is a multiple of both 24 and ...
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4answers
126 views

Find the area of a triangle given the coordinates of its vertices

The following is a GRE practice test question which I don't understand. According to this general argument, it appears that any arbitrary point $(x, 7)$ would have "height" equal to 10 but then if ...
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1answer
97 views

GRE General - How to get faster at basic math?

I've been studying for the GRE quantitative section for months, and I feel like I've hit a wall over which I cannot climb. In short, I always run out of time. As such, I get at least a quarter of the ...
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1answer
47 views

Combination problem with repetition. GRE Anagram Grid questions. Why do we divide?

So here's the first question: If 7 people board an airport shuttle with only 3 available seats, how many different seating arrangement are possible? (Assume that 3 of the 7 will actually take ...
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0answers
24 views

Question about Gre covered material Linear algebra

Sorry to bother I was unsure where to ask this. But is cramer's rule from linear algebra and adj(A) covered in the math subject GRE.
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32 views

Inequalities involving price, tax, and change

I dont understand the answer key with this math question (GRE exam): The toal amount that Bob paid for a lock was equal to the price of the lock plus a tax that was 4% of the price of the lock. Bob ...
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1answer
18 views

Repeating units digits - is this pattern meaningful or random?

I'm studying for the GRE, which often has problems involving the units digit of $n^m$, for some integers $n$ and $m$, e.g. "What is the units digit of $2^{300}$. I decided to create a table to see if ...
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1answer
83 views

compact set in lower limit topology

Let R be the set of real numbers with the topology generated by the basis {[a, b) : a < b, a, b ∈ R}. If X is the subset [0, 1] of R, which of the following must be true? (I) X is compact (II) X is ...
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55 views

function that preserves compactness

Let S be a compact topological space, let T be a topological space, and let f be a function from S onto T . Which of the following conditions on f is the weakest sufficient condition to guarantee ...
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3answers
2k views

Counting numbers in a sequence - explain “Add $1$ before you're done” rule

I'm studying for the GRE, and my study book uses a rule that it never justifies for counting numbers in a sequence: "Add $1$ before you're done." For example, how many multiples of $3$ are between ...
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1answer
33 views

Comparing binomials raised to the 8th power

The following is from a practice GRE question. I was hoping if anyone could tell me if I have reached the right conclusion for the right reasons. The question is as follows: Given that ab = 0, ...
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3answers
99 views

Is there an error in this GRE question?

I was doing a Manhattan GRE practice exam and I was sure I had cracked the twist in this one question... only to find in that there was no twist (apparently). Here is what I know: $$ \sqrt a = \pm b ...
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3answers
269 views

Are there 3 or 4 quartiles? 99 or 100 percentiles?

So I understand that a quartile is a quantile where the data is divided into four groups. 1 2 3 ---|---|---|--- And 1, 2, and 3 are the quartiles. The ...
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1answer
115 views

Is this GRE math problem wrong?

I'm working out of the Manhattan GRE test prep book and I've come across a question that I can't figure out why they chose the answer they did. "Perpendicular lines m and n intersect at point (a,b), ...
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2answers
41 views

Incomplete Question? - Ratio

I have encountered the following question in the famous "5LB book of GRE" book If the zoo currently has 80 total birds, what is the samllest number of birds that could be added such that atleast 20% ...
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2answers
47 views

Simple Ratio Question - What is wrong with my approach?

A zoo has twice as many zebras as lions and four times as many monkeys as zebras Their total is a multiple of ? (The answer is 11 but my solution gets me 13) Here is how I'm solving it: Z=2(L) -> ...
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31 views

If A/B gives __ of 3, then B must be at least 4

I had an old note that I quickly wrote and I'm really unable to read the word after 'gives'. Can someone help me out? "If A/B gives __ of 3, then B must be at least 4"
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1answer
58 views

Probabilites, Statistics and Counting Questions

I'm practicing some GRE math problems which I don't have answers for. Would you please correct my answers if they're wrong? Q1. You have 4 books, A and B and C and D. In how many ways you can ...
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2answers
70 views

Derived subsets and topological spaces

My question is regarding question $56$ from this GRE practice exam [PDF]: For a subset $S$ of a topological space $X$, let $\operatorname{cl}(S)$ denote the closure of $S$ in $X$, and let ...
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3answers
325 views

Algebra question from practice GRE exam

The following is a question from the GRE exam GR9367: Let $n > 1$ be an integer. Which of the following conditions guarantee that the equation $x^n = \sum_{i=0}^{n-1} a_ix^i$ has at least one root ...
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1answer
60 views

How to solve Work->Break->Work pattern questions?

Machine/Person A: Works for 20 hours and take break for 4 hours (repeated cycle) Machine/Person B: Works for 40 hours and take break for 8 hours (repeated cycle) In X amount of hours ( say x is ...
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2answers
296 views

Math Subject GRE 1268 Problem 64 Flux of Vector Field

What is the value of the flux of the vector field F, defined on $R^3$ by $F(x,y,z) = (x,y,z)$ through the surface $z=\sqrt{1-x^2-y^2}$ oriented with upward-pointing normal vector field? ...
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4answers
90 views

Find the approximate square root of $(a^4-a^{-4})/(a^2-a^{-2})$

Find the approximate square root of $$\dfrac{\left( \dfrac{12}{5}\right)^4 - \left( \dfrac{5}{12}\right)^4 }{\left( \dfrac{12}{5}\right)^2 - \left( \dfrac{5}{12}\right)^2}$$ I tried using the ...
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5answers
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Math Subject GRE 1268 Question 55

If $a$ and $b$ are positive numbers, what is the value of $\displaystyle \int_0^\infty \frac{e^{ax}-e^{bx}}{(1+e^{ax})(1+e^{bx})}dx$. A: $0$ B: $1$ C: $a-b$ D: $(a-b)\log 2$ E: ...
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114 views

K is the least positive integer divisible by all positive integers less than or equal to 10. Find the total number of factors of K?

the answer is 46. I am not able to figure out how to arrive at that answer