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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. 2sqrt4 + sqrt4 =
A = I (1 + rt)
3sqrt4
3
6

2. Number of degrees in a triangle
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
x= (1.2)(.8)lw
180
The point of intersection of the systems.

3. What are 'Supplementary angles?'
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
Two angles whose sum is 180.
41 - 43 - 47
A = pi(r^2)

4. P and r are factors of 100. What is greater - pr or 100?
Indeterminable.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
The steeper the slope.
3

5. Employee X is paid 19.50 per hour no matter how many a week. Employee Y earns 18 for the first 40 and 1.5 the hourly wage for every hour after that. If both earned the same amount and worked the same in one week - how many did each work?
F(x) + c
48
Angle/360 x 2(pi)r
4096

6. Define an 'expression'.
31 - 37
Area of the base X height = (pi)hr^2
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)
.0004809 X 10^11

7. 8.84 / 5.2
1:sqrt3:2
Relationship cannot be determined (what if x is negative?)
1.7
61 - 67

8. Evaluate 4/11 + 11/12
1
90 degrees
1 & 37/132
2

9. What number between 70 & 75 - inclusive - has the greatest number of factors?
4096
The set of input values for a function.
72
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

10. What are the members or elements of a set?
2.592 kg
The objects within a set.
A reflection about the axis.
(base*height) / 2

11. What transformation occurs if point C is reflected over the x-axis and then the y-axis?
A reflection about the axis.
(amount of decrease/original price) x 100%
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
x^(2(4)) =x^8 = (x^4)^2

12. (6sqrt3) x (2sqrt5) =
3
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
71 - 73 - 79
A set with a number of elements which can be counted.

13. x^2 = 9. What is the value of x?
9 & 6/7
The third side is greater than the difference and less than the sum.
3 - -3
I

14. Circumference of a circle?
Diameter(Pi)
A reflection about the origin.
The two xes after factoring.
3sqrt4

15. Which is greater? 27^(-4) or 9^(-8)
75:11
27^(-4)
2 & 3/7
1 & 37/132

16. Formula to find a circle'S circumference from its diameter?
.0004809 X 10^11
C = (pi)d
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
1:sqrt3:2

17. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
A reflection about the origin.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
An arc is a portion of a circumference of a circle.
67 - 71 - 73

18. Evaluate 3& 2/7 / 1/3
9 & 6/7
Area of the base X height = (pi)hr^2
2.592 kg
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)

19. What are the real numbers?
2
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
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)
Yes. [i.e. f(x) = x^2 - 1

20. If a=-1 and b=3 - what is the value of (4(a^3)(b^2) - 12(a^2)(b^5)) / (16(a^3)(b^2))?
20.5
An angle which is supplementary to an interior angle.
When the function is not defined for all real numbers -; only a subset of the real numbers.
12sqrt2

21. 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?
N! / (k!)(n-k)!
II
x(x - y + 1)
4a^2(b)

22. Area of a triangle?
Relationship cannot be determined (what if x is negative?)
2
(base*height) / 2
10

23. 30< all primes<40
x(x - y + 1)
A subset.
52
31 - 37

24. What is an exterior angle?
An angle which is supplementary to an interior angle.
Lies opposite the greater angle
1
Pi is the ratio of a circle'S circumference to its diameter.

25. What is an isoceles triangle?
A central angle is an angle formed by 2 radii.
Two equal sides and two equal angles.
The set of output values for a function.
130pi

26. What is the set of elements which can be found in either A or B?
(n-2) x 180
The union of A and B.
When the function is not defined for all real numbers -; only a subset of the real numbers.
Yes. [i.e. f(x) = x^2 - 1

27. The perimeter of a square is 48 inches. The length of its diagonal is:
Ax^2 + bx + c where a -b and c are constants and a /=0
...multiply by 100.
3 - -3
12sqrt2

28. x^4 + x^7 =
1/2 times 7/3
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
x^(4+7) = x^11
413.03 / 10^4 (move the decimal point 4 places to the left)

29. What are congruent triangles?
Triangles with same measure and same side lengths.
(a - b)^2
8
20.5

30. sqrt 2(sqrt 6)=
55%
Sqrt 12
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.

31. What is the measure of an exterior angle of a regular pentagon?
72
70
Move the decimal point to the right x places
4.25 - 6 - 22

32. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Area of the base X height = (pi)hr^2
The longest arc between points A and B on a circle'S diameter.
28. n = 8 - k = 2. n! / k!(n-k)!

33. What is the sum of the angles of a triangle?
Lies opposite the greater angle
The shortest arc between points A and B on a circle'S diameter.
180 degrees
Angle/360 x (pi)r^2

34. If the two sides of a triangle are unequal then the longer side...
The third side is greater than the difference and less than the sum.
Lies opposite the greater angle
413.03 / 10^4 (move the decimal point 4 places to the left)
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)

35. How many sides does a hexagon have?
x^(4+7) = x^11
6
41 - 43 - 47
4096

36. What is the order of operations?
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
Move the decimal point to the right x places
A central angle is an angle formed by 2 radii.
F(x + c)

37. What does the graph x^2 + y^2 = 64 look like?
31 - 37
1:sqrt3:2
A circle centered on the origin with radius 8.
The direction of the inequality is reversed.

38. 60 < all primes <70
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
61 - 67
A circle centered on the origin with radius 8.
(a + b)^2

39. What is a parabola?
5 OR -5
Ax^2 + bx + c where a -b and c are constants and a /=0
The steeper the slope.
6 : 1 : 2

40. a^2 - b^2
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
(a - b)(a + b)
12sqrt2
2.592 kg

41. A number is divisible by 3 if ...
The objects within a set.
70
The sum of its digits is divisible by 3.
Divide by 100.

42. What is the 'Range' of a series of numbers?
The direction of the inequality is reversed.
1:sqrt3:2
The greatest value minus the smallest.
y = (x + 5)/2

43. What is the 'Range' of a function?
The set of output values for a function.
1/2 times 7/3
... the square of the ratios of the corresponding sides.
71 - 73 - 79

44. Solve the quadratic equation ax^2 + bx + c= 0
2(pi)r^2 + 2(pi)rh
41 - 43 - 47
Pi is the ratio of a circle'S circumference to its diameter.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

45. A number is divisible by 9 if...
The sum of digits is divisible by 9.
90
9 : 25
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)

46. x^(-y)=
2 & 3/7
x(x - y + 1)
A set with a number of elements which can be counted.
1/(x^y)

47. What is the absolute value function?
Undefined
... the square of the ratios of the corresponding sides.
G(x) = {x}
70

48. A number is divisible by 6 if...
Its divisible by 2 and by 3.
31 - 37
12.5%
5

49. 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?
7 / 1000
y = 2x^2 - 3
The longest arc between points A and B on a circle'S diameter.
The overlapping sections.

50. What is the formula for compounded interest?
7 / 1000
(amount of increase/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.
An infinite set.