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

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How to write this expression about unit digits symbolically?

From a GRE book: "The units digit of a product of positive integers is equal to the units digit of the product of the units digits of those integers." I read this and was thinking... why would you ...
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1answer
52 views

What is a good combinatorics text for someone studying for the Math GRE Subject Test?

I have NEVER taken a combinatorics course, outside of what one covers in a calculus-based probability course. I would be interested in knowing what would be a suitable combinatorics text for ...
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36 views

Issue with a right-angled triangle

The area of the right angle triangle is $18\text{ cm}^2$ and the ratio of its legs is $2:3$. What is the length of the hypotenuse? I assumed the lengths of two sides to be $2x$ and $3x$. I used ...
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35 views

What information guarantees a ranking in the 90th percentile is greater than a ranking in the 70th percentile?

Consider the following facts: Person A's salary is in the 90th percentile in Company A. Person B's salary is in the 70th percentile in Company B. The question is: What piece of information is ...
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GRE Quantitative Comparison: Determining range of values satisfying equation involving absolute values

Consider the equation \begin{equation} |2a-1|+|3b+2|=0 \end{equation} Which of the following is true: $a>b$ $a<b$ $a=b$ The relationship cannot be determined. How can one solve for the ...
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213 views

GRE basic algebra problem, plugging in works, algebreic method fails me

Simple GRE practice problem, but for some reason my algebraic approach is failing me, can someone point out my error? Given: $$\theta x = x^{-3}(2x)(\frac{x}{2})(2)$$ Question: Which is greater: ...
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1answer
48 views

Average question GRE

The average daily temperature from 9th to 16th January(both inclusive) was 38.6 C and that from the 10th to 17th January(inclusive) was 39.2 C. what was the temperature on 17th January? I am able ...
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32 views

Ratio's concept in GRE question

If you can buy A apples for n nickels(five cent coin),how many apples can you buy for d times and q quarters? This Question is using Ratio's concept but the second part of the question is ...
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42 views

Bit tricky plot on GRE

In a city 90% of the population own a car, 15% own a motor cycle, and everybody owns one or the other or both. Find the percentage of motorcycle owners to car owners. In order to solve it i ...
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59 views

Tricky Question from GRE using Ratios

Of two kinds of alloy, silver and copper are contained in the ratio of $5:1$ and the other in $7:2$. What weights of the two alloys should be melted and mixed together so as to makeup a $5$ lb mass ...
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63 views

Derivative of $\int_{x}^{0} \frac{\cos xt}{t} dt$

I am working on the following problem: Find the derivative of $f(x)=\displaystyle \int_{x}^{0}\displaystyle\frac{\cos xt}{t}dt$. The answer I am supposed to get is $\displaystyle ...
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54 views

Is $\{(x,y)|y=\sin(\frac{1}{x})\}\cup(0,1)$ connected on $R^2$? [duplicate]

Source of definition: http://mathworld.wolfram.com/ConnectedSet.html Definition: A connected set is a set that cannot be partitioned into two nonempty subsets which are open in the relative topology ...
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1answer
79 views

Number of $0$ in the end of $11^n-1$

$n$ is integer, calculate number of $0$ in the end of $11^n-1$(i.e. largest integer $m$ such that $10^m|11^n-1$). The original question was $n=100$ and I could only choose $m$ from 1 to 5. I ...
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38 views

Integrating (floor(x) e^-x) from 0 to inf

How does one obtain the following result: \begin{equation} \int_0^\infty \text{floor}(x) e^{-x} dx= \frac{1}{e-1} \end{equation} where $\text{floor}(x)$ is the greatest integer not exceeding x (from ...
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1answer
45 views

Equivalent form of a double integral.

I am looking at the second question of this problem set: The iterated integral $\int_0^1 \int_{y/2}^1 e^{x^2} dx \, dy$ can be expressed as (a) $\int_0^1 \int_0^{2x} e^{x^2} dy \, dx$ ...
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1answer
31 views

Measure of angle formed by chords and two circles

The following is a question from a practice GRE Math Subject Test: In the Euclidean plane, point A is on a circle centered at point O, and O is on a circle centered at A. The circles intersect at ...
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36 views

Percentage evaulation Queestion from GRE

A question from GRE book says: A candidate who gets 30 percent marks in an examination fails by 30 marks,but another candidate who gets 42 percent marks get 42 more marks than necessary for ...
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2answers
53 views

Probability that Three Numbers Drawn Represent Sides of a Triangle

Suppose three numbers are randomly chosen from the following list: \begin{equation} 4,5,7,8,11 \end{equation} What is the probability that the numbers drawn represent sides of a triangle? I posted ...
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1answer
38 views

Equation of ellipsoid surface obtained by revolving an ellipse

I'm working through the following example from the Princeton Review book: If the ellipse $x^{2} + x^{2/9}=1$ in the $xz-$plane is revolved around the $z-$axis, what's the equation of the resulting ...
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1answer
59 views

Is it Possible to Add or Multiply Groups?

I came across a GRE Mathematics Subject test question that said the following: "Find the characteristic of the ring $Z_2 + Z_3$." The explanation of the question starts with the statement that ...
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2answers
53 views

combination problem gre @

On the new years Eve , every member of a community exchanged cards with every other member. if a total of 420 different cards were exchanged , then how many different members were there in the ...
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gre standard deviation probability

I have solved it ,but my answer is wrong above mean mean + n S.d Below mean mean-n s.d S.d' standard deviation and 'n' is number of time s.d
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2answers
55 views

Number of ways to enter 1,2,3,4,5,6 on the spots marked on three intersecting circles and have the sums of 14

How to solve it , i applied so many method but i could not find right answer, suggest me some method combination question gre 44
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Number of Abelian Groups of Order 36

GRE Subject Test Question: Up to isomorphism, how many abelian groups are there of order 36? The answer given is 4 and the explanation is as follows: Let G be an abelian group with order n. Then G ...
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Convergence of a monotonically increasing sequence

Given $a_n$ monotonically increasing and $a_n>0$. Which of the following converges? (1) $\frac{1}{a_n^2}$ (2) $e^{-a_n}$. I could not see any reason why both (1) and (2) will not converge. If ...
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straight line , gre prolem 170 score hard

what is the distance between the two straight line represented by the equation 3x+4y=10 and 6x+8y=10? A>1 B>2 C>4/3 D>1/2 E>5/2 i try to solve it , firstly find intercept of both line and then ...
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73 views

gre geometry question of 170 score level

i m thinking c is _2 And B is 2 and A point is we can find , but i am using no method only assumptions
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Geometry , gre problem

Smallest distance from a point P to any point on the circle C is 5 and the largest distance from the the point P to the circle is C is 11 . If point P is situated outside the circle C , then what is ...
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69 views

Subject GRE question - set of points of discontinuity

I was just working on a Math Subject GRE practice test, and I got the following problem wrong: Let $f$ be the function defined on the real line by $\displaystyle f(x) = \begin{cases} \displaystyle ...
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80 views

I have one month preparation. Please suggest some books.

I have one month for my GRE subjective Mathematics test. I am from India. I have learnt $75\%$ of the syllabus in my UG and high school mentioned in the ETS. I am starting today, will I be able to ...
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1answer
83 views

Probability of “either/or” and “neither” for two independent events

This is a problem from GRE quantitative section practice book. The probability of rain in Greg's town on Tuesday is $0.3$. The probability that Greg's teacher will give him a pop quiz on Tuesday is ...
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33 views

Concerning the point $(7,a)$ on the line containing $(0,0)$ and $(4,2)$

I have recently been studying to take the GRE's and while working through the math section I find a lot of problems similar to this: Now I know it is supposed to be assumed that point $O$ is marked ...
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0answers
104 views

GRE textbooks question - calculus and linear algebra

I'll be taking the Math GRE subject test in a few months. I know that it is best to focus on being able to answer all the calculus, DEs, and linear algebra questions (and quickly). I'm a pure math ...
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1answer
57 views

Left Cosets of Cyclic Subgroup

Question from a GRE Math book that I'm having trouble understanding: Find the number of left cosets of the cyclic subgroup generated by (1, 1) of $$Z_{2} \times Z_{4}$$ where Zn denotes the cyclic ...
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1answer
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Math GRE: Calculus Textbooks - is Spivak + Stewart + Rudin sufficient?

Recently, I splurged and spent $1000 in math textbooks in preparation for the Mathematics GRE subject test. So far, in terms of calculus books, I have purchased Spivak, Stewart, and Baby Rudin. Is ...
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55 views

Flower bed Walk and Area

What is a flower bed walk? I don't know what the walk is so I can't solve this problem A rectangular flower bed, dimensions 16 yards by 12 yards, is surrounded by a walk 3 yards wide. What is the ...
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Quantitative comparision between x and 1/x

Following is a GRE question called quantitative comparison. Quantity A = $x$ Quantity B = $1/x$ $-1<x<0$ Options are as follows: a) Quantity A is bigger b) ...
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Derivation of the “Combined Work Formula”

Before I get to my question, some background: Person $A$ can paint a fence at the rate $9 \frac{hour}{fence}$ (or equivalently $\frac{1}{9} \frac{fence}{hour}$) Person $B$ can paint a fence at the ...
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64 views

Finding distance using rates of change — best approach?

The question: A man drives from state $A$ to state $B$ going $60 \frac{miles}{hour}$. Then he returns from state $B$ to state $A$, driving $45 \frac{miles}{hour}$. His total driving time is $2.5 ...
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GRE - Standard Deviation

The frequency distributions shown above represent two groups of data. Each of the data values is a multiple of 10. Quantity A = The standard deviation of distribution A Quantity B = The standard ...
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58 views

GRE - Pobability Question

One person is to be selected at random from a group of 25 people. The probability that the selected person will be a male is 0.44, and the probability that the selected person will be a male who was ...
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1answer
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GRE - Probability Question

For a certain probability experiment, the probability that event $A$ will occur is $\displaystyle\frac12$ and the probability that even $B$ will occur is $\displaystyle\frac13$. Which of the following ...
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137 views

A GRE - Probability Question

In a probability experiment, G and H are independent events. The probability that G will occur is r, and the probability that H will occur is s, where both r and s are greater than 0. Quantity A The ...
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53 views

Given $(x+3)(y−4)=0$, what is the relationship between $xy$ and $-12$?

Given $(x+3)(y−4)=0 $ Quantity $A = xy $ Quantity $B = -12 $ A Quantity $A$ is greater. B Quantity $B$ is greater. C The two quantities are equal. D The relationship cannot be determined from ...
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GRE - Integer Question [closed]

How do I calculate the following? What is the sum of the odd integers from $1$ to $199$? What is the sum of the even integers from $2$ to $198$?
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A GRE Geometry Question

P, Q, and R are three points in a plane, and R does not lie on line PQ. Which of the following is true about the set of all points in the plane that are the same distance from all three points? A It ...
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94 views

Maximum Area of a Triangle when 1 Side, Perimeter Known

This is an example of a "quantitative comparison" question the GRE would test. Suppose the following information is known: one side of a triangle has length 12 the perimeter of the triangle is 40 ...
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2answers
285 views

Area of Triangle when 2 Sides and No Angle Known

It is quite possible this question has no answer -- that is, the area cannot be determined from the information given. It's a question I've created myself as I study for the GRE. No trigonometry is ...
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2answers
75 views

Finding the possible dimensions of the intersection of subspaces

I read this problem, If $V$ and $W$ are 2-dimensional subspaces of $\mathbb{R}^{4}$ what are the possible dimensions of $V\cap W$? I know the answer is: 0, 1, or 2. But I would like more insight ...
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71 views

Solving $4a+5b=27$ where $a,b$ are two different positive integers

This problem is making my head spin: The costs of equities of symbol A and symbol B (in dollars) are two different positive integers. If $4$ equities of symbol A and $5$ equities of symbol B together ...