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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. What are complementary angles?
Two angles whose sum is 90.
Cd
$3 -500 in the 9% and $2 -500 in the 7%.
27^(-4)

2. 413.03 x 10^(-4) =
An isosceles right triangle.
62.5%
413.03 / 10^4 (move the decimal point 4 places to the left)
2(pi)r^2 + 2(pi)rh

3. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
An infinite set.
13
y = (x + 5)/2
70

4. Simplify the expression [(b^2 - c^2) / (b - c)]
72
(b + c)
N! / (n-k)!
Two angles whose sum is 90.

5. What is the name of set with a number of elements which cannot be counted?
1.0843 X 10^11
An infinite set.
61 - 67
1 & 37/132

6. If you have a set of n objects - but you only want to order k of them - what formula do you use to determine the number of permutations?
Two angles whose sum is 180.
N! / (n-k)!
(amount of increase/original price) x 100%
180

7. What is the empty set?
180
A set with no members - denoted by a circle with a diagonal through it.
A 30-60-90 triangle.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

8. Reduce: 4.8 : 0.8 : 1.6
6 : 1 : 2
Ax^2 + bx + c where a -b and c are constants and a /=0
The third side is greater than the difference and less than the sum.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

9. What is the sum of the angles of a triangle?
180 degrees
No - only like radicals can be added.
The overlapping sections.
The sum of digits is divisible by 9.

10. When the 'a' in a parabola is positive....
The curve opens upward and the vertex is the minimal point on the graph.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
No - the input value has exactly one output.
The direction of the inequality is reversed.

11. What is the 'Solution' for a set of inequalities.
The overlapping sections.
F(x + c)
Cd
Yes. [i.e. f(x) = x^2 - 1

12. (12sqrt15) / (2sqrt5) =
500
11 - 13 - 17 - 19
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
An arc is a portion of a circumference of a circle.

13. Simplify the expression (p^2 - q^2)/ -5(q - p)
1/(x^y)
(p + q)/5
12sqrt2
5

14. 60 < all primes <70
x^(4+7) = x^11
61 - 67
(amount of increase/original price) x 100%
70

15. Formula for the area of a circle?
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)
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
A = pi(r^2)
(a + b)^2

16. 10^6 has how many zeroes?
Indeterminable.
An infinite set.
A tangent is a line that only touches one point on the circumference of a circle.
6

17. To convert a percent to a fraction....
Divide by 100.
12sqrt2
The sum of digits is divisible by 9.
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)

18. 10<all primes<20
11 - 13 - 17 - 19
N! / (k!)(n-k)!
1/2 times 7/3
130pi

19. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
The direction of the inequality is reversed.
180
28. n = 8 - k = 2. n! / k!(n-k)!
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

20. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
4:5
The third side is greater than the difference and less than the sum.
An arc is a portion of a circumference of a circle.
x(x - y + 1)

21. What are the real numbers?
The interesection of A and B.
70
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)
48

22. What is the surface area of a cylinder with radius 5 and height 8?
130pi
The sum of digits is divisible by 9.
4:5
No - only like radicals can be added.

23. What is an isoceles triangle?
The longest arc between points A and B on a circle'S diameter.
Sqrt 12
Two equal sides and two equal angles.
Angle/360 x 2(pi)r

24. What does the graph x^2 + y^2 = 64 look like?
A circle centered at -2 - -2 with radius 3.
72
41 - 43 - 47
A circle centered on the origin with radius 8.

25. x^2 = 9. What is the value of x?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
75:11
3 - -3
0

26. What is the ratio of the sides of a 30-60-90 triangle?
An angle which is supplementary to an interior angle.
1:sqrt3:2
28. n = 8 - k = 2. n! / k!(n-k)!
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

27. x^4 + x^7 =
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
The interesection of A and B.
0
x^(4+7) = x^11

28. How to find the diagonal of a rectangular solid?
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
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...
Infinite.
1/2 times 7/3

29. What is the 'union' of A and B?
... the square of the ratios of the corresponding sides.
The set of elements which can be found in either A or B.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
Triangles with same measure and same side lengths.

30. 1/6 in percent?
Infinite.
1
4096
16.6666%

31. Formula to find a circle'S circumference from its diameter?
C = (pi)d
N! / (n-k)!
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
x^(4+7) = x^11

32. 4.809 X 10^7 =
28. n = 8 - k = 2. n! / k!(n-k)!
Diameter(Pi)
.0004809 X 10^11
67 - 71 - 73

33. What is a piecewise equation?
1/2 times 7/3
(a + b)^2
Undefined - because we can'T divide by 0.
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

34. A brick with dimensions 10. 15 and 25 weighs 1.5 kg. A second brick (same density) has dimensions 12 - 18 - and 30. What is the weight of the second brick?
1
Triangles with same measure and same side lengths.
2.592 kg
IV

35. (6sqrt3) x (2sqrt5) =
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
(a + b)^2
10
x^(4+7) = x^11

36. Surface area for a cylinder?
x^(2(4)) =x^8 = (x^4)^2
Two equal sides and two equal angles.
2(pi)r^2 + 2(pi)rh
Move the decimal point to the right x places

37. What is the graph of f(x) shifted upward c units or spaces?
1
x^(2(4)) =x^8 = (x^4)^2
F(x) + c
Undefined

38. Which is greater? 200x^295 or 10x^294?
(a - b)(a + b)
Relationship cannot be determined (what if x is negative?)
The empty set - denoted by a circle with a diagonal through it.
F(x) - c

39. What is a parabola?
(p + q)/5
16.6666%
Ax^2 + bx + c where a -b and c are constants and a /=0
2.592 kg

40. Legs 6 - 8. Hypotenuse?
Ax^2 + bx + c where a -b and c are constants and a /=0
C = 2(pi)r
10
9 : 25

41. Length of an arc of a circle?
Angle/360 x 2(pi)r
16.6666%
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The overlapping sections.

42. For similar triangles - the ratio of their corresponding sides is 2:3. What is the ratio of their areas?
A set with a number of elements which can be counted.
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
A circle centered on the origin with radius 8.
An arc is a portion of a circumference of a circle.

43. Whats the difference between factors and multiples?
True
Factors are few - multiples are many.
Infinite.
1.0843 X 10^11

44. a^2 + 2ab + b^2
9 & 6/7
N! / (n-k)!
(a + b)^2
...multiply by 100.

45. Order of quadrants:
72
From northeast - counterclockwise. I - II - III - IV
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

46. What is a tangent?
1:sqrt3:2
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
(a - b)^2
A tangent is a line that only touches one point on the circumference of a circle.

47. 5x^2 - 35x -55 = 0
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
II
The direction of the inequality is reversed.
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)

48. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
1:1:sqrt2
A circle centered at -2 - -2 with radius 3.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
Two equal sides and two equal angles.

49. Describe the relationship between 3x^2 and 3(x - 1)^2
31 - 37
6
13
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

50. Which quadrant is the upper right hand?
53 - 59
Undefined - because we can'T divide by 0.
A set with no members - denoted by a circle with a diagonal through it.
I