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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 the real numbers?
... the square of the ratios of the corresponding sides.
A central angle is an angle formed by 2 radii.
10! / (10-3)! = 720
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)

2. To convert a decimal to a percent...
9 : 25
4096
...multiply by 100.
x^(2(4)) =x^8 = (x^4)^2

3. 4.809 X 10^7 =
500
Even
.0004809 X 10^11
41 - 43 - 47

4. What is the surface area of a cylinder with radius 5 and height 8?
90pi
A set with no members - denoted by a circle with a diagonal through it.
Divide by 100.
130pi

5. x^6 / x^3
Yes - like radicals can be added/subtracted.
11 - 13 - 17 - 19
x^(6-3) = x^3
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

6. If Madagascar'S exports totaled 1.3 billion in 2009 - and 4% came from China - what was the value in millions of the country'S exports to China?
Sector area = (n/360) X (pi)r^2
x(x - y + 1)
Undefined - because we can'T divide by 0.
52

7. What is the slope of a horizontal line?
0
4:5
Angle/360 x 2(pi)r
F(x) + c

8. (12sqrt15) / (2sqrt5) =
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
18
Factors are few - multiples are many.
The second graph is less steep.

9. 50 < all primes< 60
53 - 59
The direction of the inequality is reversed.
10! / 3!(10-3)! = 120
Its negative reciprocal. (-b/a)

10. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
70
The curve opens upward and the vertex is the minimal point on the graph.
Triangles with same measure and same side lengths.
75:11

11. Convert 0.7% to a fraction.
7 / 1000
Ax^2 + bx + c where a -b and c are constants and a /=0
Arc length = (n/360) x pi(2r) where n is the number of degrees.
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. Evaluate (4^3)^2
An arc is a portion of a circumference of a circle.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
A = I (1 + rt)
4096

13. What is the ratio of the sides of an isosceles right triangle?
1:1:sqrt2
C = 2(pi)r
Members or elements
10! / 3!(10-3)! = 120

14. Surface area for a cylinder?
Triangles with same measure and same side lengths.
2(pi)r^2 + 2(pi)rh
41 - 43 - 47
No - only like radicals can be added.

15. Whats the difference between factors and multiples?
(a - b)^2
Factors are few - multiples are many.
A = I (1 + rt)
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

16. How to determine percent decrease?
23 - 29
(amount of decrease/original price) x 100%
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
Two angles whose sum is 90.

17. Which is greater? 27^(-4) or 9^(-8)
27^(-4)
130pi
1/a^6
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

18. Define an 'expression'.
0
An isosceles right triangle.
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)
87.5%

19. Describe the relationship between the graphs of x^2 and (1/2)x^2
The curve opens downward and the vertex is the maximum point on the graph.
F(x + c)
The second graph is less steep.
Pi is the ratio of a circle'S circumference to its diameter.

20. What is the graph of f(x) shifted upward c units or spaces?
(n-2) x 180
4:5
F(x) + c
31 - 37

21. Formula to find a circle'S circumference from its radius?
288 (8 9 4)
C = 2(pi)r
41 - 43 - 47
No - only like radicals can be added.

22. What is the formula for compounded interest?
3
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)
8
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.

23. Legs 6 - 8. Hypotenuse?
10
(base*height) / 2
11 - 13 - 17 - 19
62.5%

24. Area of a triangle?
F(x + c)
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
Yes. [i.e. f(x) = x^2 - 1
(base*height) / 2

25. When the 'a' in a parabola is positive....
The curve opens upward and the vertex is the minimal point on the graph.
G(x) = {x}
A reflection about the axis.
72

26. What are the members or elements of a set?
The objects within a set.
2
The curve opens upward and the vertex is the minimal point on the graph.
1

27. In a triangle where the two legs are 4 and 3 - what is the value of a line directly intersecting the middle coming from the meeting point of the two legs?
20.5
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
53 - 59
I

28. 0^0
5 OR -5
Undefined
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
130pi

29. Can you simplify sqrt72?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
5
The direction of the inequality is reversed.
A = I (1 + rt)

30. 70 < all primes< 80
1
The curve opens upward and the vertex is the minimal point on the graph.
61 - 67
71 - 73 - 79

31. 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?
The curve opens upward and the vertex is the minimal point on the graph.
F(x) - c
Undefined
y = 2x^2 - 3

32. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
1
C = (pi)d
9 : 25
The sum of digits is divisible by 9.

33. A number is divisible by 6 if...
Its divisible by 2 and by 3.
Even
12! / 5!7! = 792
23 - 29

34. How many multiples does a given number have?
1/2 times 7/3
23 - 29
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
Infinite.

35. x^2 = 9. What is the value of x?
True
F(x + c)
3 - -3
The overlapping sections.

36. Simplify the expression (p^2 - q^2)/ -5(q - p)
23 - 29
(p + q)/5
2
Infinite.

37. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
83.333%
4:5
2sqrt6
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

38. What is the area of a regular hexagon with side 6?
9 : 25
The point of intersection of the systems.
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
2(pi)r^2 + 2(pi)rh

39. Which quadrant is the lower left hand?
F(x-c)
III
16.6666%
A circle centered on the origin with radius 8.

40. x^(-y)=
N! / (k!)(n-k)!
1/(x^y)
The second graph is less steep.
II

41. What is the maximum value for the function g(x) = (-2x^2) -1?
75:11
1
(a + b)^2
16.6666%

42. Volume for a cylinder?
A 30-60-90 triangle.
2^9 / 2 = 256
Area of the base X height = (pi)hr^2
x(x - y + 1)

43. 6w^2 - w - 15 = 0
The second graph is less steep.
75:11
3/2 - 5/3
87.5%

44. What is the 'Restricted domain of a function'?
The two xes after factoring.
37.5%
The sum of digits is divisible by 9.
When the function is not defined for all real numbers -; only a subset of the real numbers.

45. Factor x^2 - xy + x.
72
x(x - y + 1)
Two equal sides and two equal angles.
13pi / 2

46. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
F(x) + c
10! / 3!(10-3)! = 120
An isosceles right triangle.
7 / 1000

47. The larger the absolute value of the slope...
True
The steeper the slope.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
Yes. [i.e. f(x) = x^2 - 1

48. 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?
10! / 3!(10-3)! = 120
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
72
28. n = 8 - k = 2. n! / k!(n-k)!

49. Can the output value of a function have more than one input value?
Yes. [i.e. f(x) = x^2 - 1
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
Lies opposite the greater angle
4:5

50. What are the integers?
G(x) = {x}
All numbers multiples of 1.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
Triangles with same measure and same side lengths.