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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. 70 < all primes< 80
x(x - y + 1)
Angle/360 x (pi)r^2
(a - b)(a + b)
71 - 73 - 79

2. Define an 'expression'.
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)
5
52
Its negative reciprocal. (-b/a)

3. What are complementary angles?
(a - b)(a + b)
x^(2(4)) =x^8 = (x^4)^2
The third side is greater than the difference and less than the sum.
Two angles whose sum is 90.

4. Solve the quadratic equation ax^2 + bx + c= 0
The set of output values for a function.
1
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

5. If an inequality is multiplied or divided by a negative number....
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
The direction of the inequality is reversed.
Ax^2 + bx + c where a -b and c are constants and a /=0
16.6666%

6. Factor a^2 + 2ab + b^2
(a + b)^2
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
...multiply by 100.
41 - 43 - 47

7. What is the 'union' of A and B?
The curve opens downward and the vertex is the maximum point on the graph.
4a^2(b)
7 / 1000
The set of elements which can be found in either A or B.

8. What are the members or elements of a set?
The objects within a set.
Its divisible by 2 and by 3.
Lies opposite the greater angle
Infinite.

9. Which quadrant is the upper left hand?
II
7 / 1000
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)
Pi is the ratio of a circle'S circumference to its diameter.

10. What is an exterior angle?
11 - 13 - 17 - 19
No - only like radicals can be added.
An angle which is supplementary to an interior angle.
72

11. What is a central angle?
A central angle is an angle formed by 2 radii.
Area of the base X height = (pi)hr^2
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
No - the input value has exactly one output.

12. What is a set with no members called?
(a - b)(a + b)
IV
67 - 71 - 73
The empty set - denoted by a circle with a diagonal through it.

13. What does the graph x^2 + y^2 = 64 look like?
A circle centered on the origin with radius 8.
F(x) - c
The curve opens downward and the vertex is the maximum point on the graph.
C = (pi)d

14. Simplify the expression [(b^2 - c^2) / (b - c)]
(a - b)^2
A circle centered on the origin with radius 8.
Ax^2 + bx + c where a -b and c are constants and a /=0
(b + c)

15. 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
The curve opens upward and the vertex is the minimal point on the graph.
Even
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

16. 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?
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
0
(n-2) x 180
87.5%

17. What is the 'domain' of a function?
(a - b)(a + b)
2^9 / 2 = 256
The set of input values for a function.
.0004809 X 10^11

18. How to determine percent decrease?
A circle centered on the origin with radius 8.
An expression with just one term (-6x - 2a^2)
5
(amount of decrease/original price) x 100%

19. Factor x^2 - xy + x.
4.25 - 6 - 22
x(x - y + 1)
Yes - like radicals can be added/subtracted.
41 - 43 - 47

20. P and r are factors of 100. What is greater - pr or 100?
Indeterminable.
No - the input value has exactly one output.
x^(4+7) = x^11
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)

21. 1/6 in percent?
16.6666%
The direction of the inequality is reversed.
3 - -3
x^(2(4)) =x^8 = (x^4)^2

22. Which quadrant is the lower left hand?
III
Members or elements
An infinite set.
Its negative reciprocal. (-b/a)

23. 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?
130pi
Cd
2.592 kg
27^(-4)

24. The perimeter of a square is 48 inches. The length of its diagonal is:
12sqrt2
y = 2x^2 - 3
An infinite set.
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)

25. Area of a triangle?
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
(base*height) / 2
An expression with just one term (-6x - 2a^2)
500

26. What are the roots of the quadrinomial x^2 + 2x + 1?
A grouping of the members within a set based on a shared characteristic.
A subset.
The interesection of A and B.
The two xes after factoring.

27. Legs: 3 - 4. Hypotenuse?
4a^2(b)
All numbers multiples of 1.
5
4096

28. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
I
2sqrt6
y = (x + 5)/2

29. What is the graph of f(x) shifted upward c units or spaces?
A central angle is an angle formed by 2 radii.
F(x) + c
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)
3 - -3

30. 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?
1
9 : 25
83.333%
An arc is a portion of a circumference of a circle.

31. Find the surface area of a cylinder with radius 3 and height 12.
90pi
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
3/2 - 5/3
2^9 / 2 = 256

32. Simplify (a^2 + b)^2 - (a^2 - b)^2
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
An isosceles right triangle.
4a^2(b)
83.333%

33. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
x(x - y + 1)
(base*height) / 2
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
An isosceles right triangle.

34. 10<all primes<20
27^(-4)
1
4:5
11 - 13 - 17 - 19

35. 4.809 X 10^7 =
F(x + c)
75:11
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
.0004809 X 10^11

36. 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)?
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
(amount of decrease/original price) x 100%
y = (x + 5)/2
F(x) - c

37. Order of quadrants:
2
IV
An arc is a portion of a circumference of a circle.
From northeast - counterclockwise. I - II - III - IV

38. When the 'a' in a parabola is positive....
The curve opens upward and the vertex is the minimal point on the graph.
0
IV
9 : 25

39. Evaluate (4^3)^2
The shortest arc between points A and B on a circle'S diameter.
71 - 73 - 79
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
4096

40. 25^(1/2) or sqrt. 25 =
5 OR -5
x^(4+7) = x^11
Yes. [i.e. f(x) = x^2 - 1
The third side is greater than the difference and less than the sum.

41. How many sides does a hexagon have?
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
37.5%
6
Part = Percent X Whole

42. Evaluate 4/11 + 11/12
Its last two digits are divisible by 4.
13pi / 2
1 & 37/132
A circle centered on the origin with radius 8.

43. 20<all primes<30
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
23 - 29
90
(a + b)^2

44. A number is divisible by 9 if...
The sum of digits is divisible by 9.
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 grouping of the members within a set based on a shared characteristic.
3 - -3

45. 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)]?
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
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)
72
True

46. Which is greater? 27^(-4) or 9^(-8)
All numbers multiples of 1.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The objects within a set.
27^(-4)

47. 1/2 divided by 3/7 is the same as
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.
1/2 times 7/3
Undefined - because we can'T divide by 0.
3

48. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
5
An angle which is supplementary to an interior angle.
90
7 / 1000

49. Formula for the area of a circle?
(amount of increase/original price) x 100%
A = pi(r^2)
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)
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)

50. What are the smallest three prime numbers greater than 65?
67 - 71 - 73
G(x) = {x}
I
III