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GRE Math: Common Errors

Subjects : gre, math

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Which is greater? 27^(-4) or 9^(-8)
All numbers multiples of 1.
27^(-4)
Pi is the ratio of a circle'S circumference to its diameter.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

2. sqrt 2(sqrt 6)=
Sqrt 12
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
A grouping of the members within a set based on a shared characteristic.
From northeast - counterclockwise. I - II - III - IV

3. The slope of a line perpendicular to (a/b)?
(a + b)^2
C = (pi)d
All numbers multiples of 1.
Its negative reciprocal. (-b/a)

4. When does a function automatically have a restricted domain (2)?
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
Infinite.
The shortest arc between points A and B on a circle'S diameter.
IV

5. There are 10 finalists for the school spelling bee. A first - second - and third place trophy will be awarded. How many different people can get the three prizes?
Yes. [i.e. f(x) = x^2 - 1
The union of A and B.
10! / 3!(10-3)! = 120
288 (8 9 4)

6. 5 bakeries sell an average of 300 muffins per bakery per day. If 2 stop making muffins but the total muffins sold stays the same - what is the average of muffins per bakery sold among the remaining?
The set of elements found in both A and B.
500
When the function is not defined for all real numbers -; only a subset of the real numbers.
G(x) = {x}

7. 1/2 divided by 3/7 is the same as
1/2 times 7/3
The shortest arc between points A and B on a circle'S diameter.
55%
True

8. Legs 5 - 12. Hypotenuse?
13
1/2 times 7/3
All numbers multiples of 1.
x= (1.2)(.8)lw

9. How many digits are there between the decimal point and the first even digit in the decimal equivalent of 1/[(2^8)(5^3)]
Undefined - because we can'T divide by 0.
23 - 29
5
0

10. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
2.592 kg
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
The interesection of A and B.
(b + c)

11. Describe the relationship between the graphs of x^2 and (1/2)x^2
The second graph is less steep.
F(x-c)
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
Angle/360 x (pi)r^2

12. 40 < all primes<50
41 - 43 - 47
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
I
The objects within a set.

13. What is a central angle?
4sqrt3. The triangle can be divided into two equal 30-60-90 triangles with side 6 as the side in which 6 = xsqrt3. So x =2sqrt3...
A central angle is an angle formed by 2 radii.
The steeper the slope.
62.5%

14. What are the real numbers?
3 - -3
The two xes after factoring.
x^(4+7) = x^11
All the numbers on the number line (negative - rational - irrational - decimal - integer). All the numbers on the GRE are real. (-2 - 1 - .25 - 1/2 - pi)

15. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
3
The point of intersection of the systems.
Even
(a + b)^2

16. Ratio of ages of Anna and Emma is 3:5 and of Emma and Nicolas is 3:5. What is the ratio of Anna to Nicholas' ages?
0
Angle/360 x 2(pi)r
9 : 25
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

17. What is the 'Solution' for a system of linear equations?
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
13pi / 2
The point of intersection of the systems.
2sqrt6

18. What is the maximum value for the function g(x) = (-2x^2) -1?
The union of A and B.
7 / 1000
Indeterminable.
1

19. Simplify the expression [(b^2 - c^2) / (b - c)]
1:sqrt3:2
(b + c)
1:1:sqrt2
Sqrt 12

20. Simplify (a^2 + b)^2 - (a^2 - b)^2
4a^2(b)
1 & 37/132
The curve opens downward and the vertex is the maximum point on the graph.
Factors are few - multiples are many.

21. The ratio of the areas of two similar polygons is ...
IV
Indeterminable.
0
... the square of the ratios of the corresponding sides.

22. What is the empty set?
A set with no members - denoted by a circle with a diagonal through it.
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
$11 -448
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)

23. 10<all primes<20
3
(amount of decrease/original price) x 100%
A= I (1 + (r/c))^tC - where I is the investment - C is the number of times compounded annually - and t is the number of years.
11 - 13 - 17 - 19

24. What is the percent formula?
2
Part = Percent X Whole
... the square of the ratios of the corresponding sides.
Undefined - because we can'T divide by 0.

25. Legs: 3 - 4. Hypotenuse?
2
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
Undefined - because we can'T divide by 0.
5

26. What is the measure of an exterior angle of a regular pentagon?
0
72
Its divisible by 2 and by 3.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

27. Factor x^2 - xy + x.
x(x - y + 1)
Sector area = (n/360) X (pi)r^2
9 : 25
An isosceles right triangle.

28. What is the ratio of the surface area of a cube with an edge of 10 to the surface area of a rectangular solid with dimensions 2 - 4 - and 6?
II
The steeper the slope.
75:11
x^(4+7) = x^11

29. What are complementary angles?
F(x) - c
12! / 5!7! = 792
Part = Percent X Whole
Two angles whose sum is 90.

30. 1/6 in percent?
16.6666%
The set of elements found in both A and B.
Infinite.
3

31. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
2 & 3/7
70
2(pi)r^2 + 2(pi)rh
An algebraic expression is a combination of one of more terms. Terms in an expression are separated by either addition or subtraction signs. (3xy - 4ab - -5cd - x^2 + x - 1)

32. 5x^2 - 35x -55 = 0
Diameter(Pi)
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
28. n = 8 - k = 2. n! / k!(n-k)!

33. Can you add sqrt 3 and sqrt 5?
No - only like radicals can be added.
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
4:5
Sqrt 12

34. What is the graph of f(x) shifted downward c units or spaces?
N! / (k!)(n-k)!
F(x) - c
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
The set of output values for a function.

35. (12sqrt15) / (2sqrt5) =
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
(amount of increase/original price) x 100%
1:sqrt3:2
y = (x + 5)/2

36. Suppose that the graph of f(x) is the result of sliding the graph of y=2x^2 down 3 units of spaces. What is the new equation?
y = 2x^2 - 3
The greatest value minus the smallest.
288 (8 9 4)
(n-2) x 180

37. 25^(1/2) or sqrt. 25 =
1
Cd
5 OR -5
Angle/360 x (pi)r^2

38. Write 10 -843 X 10^7 in scientific notation
Triangles with same measure and same side lengths.
10! / (10-3)! = 720
Ax^2 + bx + c where a -b and c are constants and a /=0
1.0843 X 10^11

39. Evaluate 3& 2/7 / 1/3
0
9 & 6/7
N! / (n-k)!
18

40. A number is divisible by 6 if...
12.5%
(a + b)^2
20.5
Its divisible by 2 and by 3.

41. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
Relationship cannot be determined (what if x is negative?)
4096
4:5
A circle centered on the origin with radius 8.

42. What is a chord of a circle?
An infinite set.
2.592 kg
A chord is a line segment joining two points on a circle.
A tangent is a line that only touches one point on the circumference of a circle.

43. What are the integers?
All numbers multiples of 1.
2.592 kg
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
12.5%

44. T or F? Given d -e &f =/ 0 - [(d^3)e(f^5)] / 2d(e^3) / [3(d^2)(e^3)(f^7)] / [6(e^5)(f^2)]?
1/a^6
71 - 73 - 79
True
10

45. What is a minor arc?

46. What transformation occurs if point C is reflected over the x-axis and then the y-axis?
Indeterminable.
A reflection about the axis.
The shortest arc between points A and B on a circle'S diameter.
9 & 6/7

47. The objects in a set are called two names:
7 / 1000
72
A central angle is an angle formed by 2 radii.
Members or elements

48. Convert 0.7% to a fraction.
(a + b)^2
4sqrt3. The triangle can be divided into two equal 30-60-90 triangles with side 6 as the side in which 6 = xsqrt3. So x =2sqrt3...
7 / 1000
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

49. What is the surface area of a cylinder with radius 5 and height 8?
Area of the base X height = (pi)hr^2
130pi
An isosceles right triangle.
1

50. What are the rational numbers?
The overlapping sections.
180
83.333%
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)