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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. Length of an arc of a circle?
90
Angle/360 x 2(pi)r
27^(-4)
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

2. 25^(1/2) or sqrt. 25 =
3
(amount of increase/original price) x 100%
1
5 OR -5

3. The slope of a line perpendicular to (a/b)?
Cd
Its negative reciprocal. (-b/a)
y = 2x^2 - 3
The set of input values for a function.

4. Legs: 3 - 4. Hypotenuse?
Its negative reciprocal. (-b/a)
5
90pi
A tangent is a line that only touches one point on the circumference of a circle.

5. x^6 / x^3
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
x^(6-3) = x^3
The interesection of A and B.
413.03 / 10^4 (move the decimal point 4 places to the left)

6. What is the area of a regular hexagon with side 6?
13pi / 2
3 - -3
Triangles with same measure and same side lengths.
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

7. What is the slope of a vertical line?

8. What is a major arc?

9. Which quadrant is the upper left hand?
0
II
12.5%
The steeper the slope.

10. To convert a percent to a fraction....
The steeper the slope.
Divide by 100.
A = pi(r^2)
(a - b)(a + b)

11. What are the integers?
61 - 67
A circle centered on the origin with radius 8.
All numbers multiples of 1.
1

12. 10<all primes<20
A set with a number of elements which can be counted.
11 - 13 - 17 - 19
C = (pi)d
10

13. 1/8 in percent?
10! / (10-3)! = 720
1
12.5%
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

14. x^4 + x^7 =
x^(4+7) = x^11
Sector area = (n/360) X (pi)r^2
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

15. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
Members or elements
2sqrt6
(a - b)(a + b)
The shortest arc between points A and B on a circle'S diameter.

16. What is the maximum value for the function g(x) = (-2x^2) -1?
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)
1
(b + c)
48

17. What are 'Supplementary angles?'
11 - 13 - 17 - 19
.0004809 X 10^11
Two angles whose sum is 180.
Sector area = (n/360) X (pi)r^2

18. What is a finite set?
A set with a number of elements which can be counted.
Triangles with same measure and same side lengths.
6
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

19. What is the percent formula?
x(x - y + 1)
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
Part = Percent X Whole
2 & 3/7

20. What are the smallest three prime numbers greater than 65?
67 - 71 - 73
53 - 59
Pi is the ratio of a circle'S circumference to its diameter.
... the square of the ratios of the corresponding sides.

21. 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?
N! / (n-k)!
72
The set of elements which can be found in either A or B.
Two angles whose sum is 180.

22. What is a piecewise equation?
Pi is the ratio of a circle'S circumference to its diameter.
67 - 71 - 73
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
(a + b)^2

23. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
C = (pi)d
2(pi)r^2 + 2(pi)rh
6
A 30-60-90 triangle.

24. Suppose you have a set of n objects - and you want to select k of them - but the order doesn'T matter. What formula do you use to determine the number of combinations of n objects taken k at a time?
1/2 times 7/3
10! / (10-3)! = 720
N! / (k!)(n-k)!
No - the input value has exactly one output.

25. Convert 0.7% to a fraction.
The direction of the inequality is reversed.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
The set of elements found in both A and B.
7 / 1000

26. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
(a - b)^2
.0004809 X 10^11
An arc is a portion of a circumference of a circle.
12! / 5!7! = 792

27. What are complementary angles?
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
8
x^(2(4)) =x^8 = (x^4)^2
Two angles whose sum is 90.

28. If r - t - s & u are distinct - consecutive prime numbers - less than 31 - which of the following could be an average of them (4 - 4.25 - 6 - 9 - 24 - 22 - 24)
F(x-c)
Lies opposite the greater angle
4.25 - 6 - 22
2

29. 5/6 in percent?
83.333%
3
The steeper the slope.
x^(4+7) = x^11

30. If the two sides of a triangle are unequal then the longer side...
2sqrt6
Undefined - because we can'T divide by 0.
(p + q)/5
Lies opposite the greater angle

31. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
A circle centered at -2 - -2 with radius 3.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
A subset.
70

32. What is the 'domain' of a function?
The set of input values for a function.
67 - 71 - 73
... the square of the ratios of the corresponding sides.
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)

33. What is the 'Solution' for a set of inequalities.
0
The overlapping sections.
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
87.5%

34. What is the graph of f(x) shifted left c units or spaces?
A set with no members - denoted by a circle with a diagonal through it.
x^(6-3) = x^3
F(x + c)
III

35. Formula to calculate arc length?
A circle centered on the origin with radius 8.
I
3/2 - 5/3
Arc length = (n/360) x pi(2r) where n is the number of degrees.

36. Legs 5 - 12. Hypotenuse?
13
F(x) + c
The steeper the slope.
Members or elements

37. 30< all primes<40
31 - 37
3 - -3
4096
Lies opposite the greater angle

38. Suppose that the graph of f(x) is the result of stretching y=x + 5 away from the x-axis by a factor of 2. What is the new equation for the graph f(x)?
2.4. We calculate the area (6) and then turn the triangle on its side and use x as the height to calculate again. (5x)/2=6
8
y = (x + 5)/2
...multiply by 100.

39. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
Indeterminable.
$11 -448
... the square of the ratios of the corresponding sides.
1

40. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
2
An isosceles right triangle.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

41. 6w^2 - w - 15 = 0
3/2 - 5/3
1.7
13
75:11

42. What is the order of operations?
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
0
Infinite.
90

43. (6sqrt3) x (2sqrt5) =
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
(a - b)(a + b)
48
16.6666%

44. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
No - only like radicals can be added.
500
The union of A and B.
70

45. 1/6 in percent?
3/2 - 5/3
x(x - y + 1)
16.6666%
4:5

46. Surface area for a cylinder?
2(pi)r^2 + 2(pi)rh
72
67 - 71 - 73
61 - 67

47. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
The curve opens downward and the vertex is the maximum point on the graph.
The empty set - denoted by a circle with a diagonal through it.
8

48. What is the formula for computing simple interest?
A = I (1 + rt)
(a + b)^2
The empty set - denoted by a circle with a diagonal through it.
A set with no members - denoted by a circle with a diagonal through it.

49. What is a subset?
4725
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
A grouping of the members within a set based on a shared characteristic.

50. a^0 =
2(pi)r^2 + 2(pi)rh
The union of A and B.
1
12sqrt2