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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 is a parabola?
Ax^2 + bx + c where a -b and c are constants and a /=0
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
(a - 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.

2. Simplify the expression [(b^2 - c^2) / (b - c)]
A = pi(r^2)
(b + c)
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
41 - 43 - 47

3. What is the sum of the angles of a triangle?
61 - 67
18
180 degrees
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)

4. Formula for the area of a circle?
The set of output values for a function.
A = pi(r^2)
Lies opposite the greater angle
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

5. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
The steeper the slope.
72
4096
$11 -448

6. What is the 'Solution' for a set of inequalities.
Two angles whose sum is 90.
y = 2x^2 - 3
The overlapping sections.
28. n = 8 - k = 2. n! / k!(n-k)!

7. Max and Min lengths for a side of a triangle?
A grouping of the members within a set based on a shared characteristic.
The third side is greater than the difference and less than the sum.
No - only like radicals can be added.
70

8. Length of an arc of a circle?
Angle/360 x 2(pi)r
...multiply by 100.
The sum of its digits is divisible by 3.
3sqrt4

9. What is the name of set with a number of elements which cannot be counted?
Diameter(Pi)
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
5
An infinite set.

10. 1/8 in percent?
1
67 - 71 - 73
C = (pi)d
12.5%

11. What does scientific notation mean?
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
The set of elements which can be found in either A or B.
71 - 73 - 79
An infinite set.

12. What is an isoceles triangle?
2.592 kg
Two equal sides and two equal angles.
6
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

13. Factor a^2 + 2ab + b^2
Two angles whose sum is 90.
True
1.7
(a + b)^2

14. To convert a decimal to a percent...
72
...multiply by 100.
48
4.25 - 6 - 22

15. What is the maximum value for the function g(x) = (-2x^2) -1?
The sum of digits is divisible by 9.
1:sqrt3:2
1
Angle/360 x (pi)r^2

16. Write 10 -843 X 10^7 in scientific notation
1.0843 X 10^11
The longest arc between points A and B on a circle'S diameter.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
The sum of digits is divisible by 9.

17. What is a tangent?
A tangent is a line that only touches one point on the circumference of a circle.
The third side is greater than the difference and less than the sum.
The two xes after factoring.
1:1:sqrt2

18. What is the slope of a horizontal line?
y = 2x^2 - 3
Cd
53 - 59
0

19. 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)?
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.
F(x) - c
y = (x + 5)/2
(base*height) / 2

20. Legs: 3 - 4. Hypotenuse?
1.7
90 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)
5

21. 5x^2 - 35x -55 = 0
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
2sqrt6
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)
13pi / 2

22. (a^-1)/a^5
From northeast - counterclockwise. I - II - III - IV
A circle centered on the origin with radius 8.
2 & 3/7
1/a^6

23. Legs 6 - 8. Hypotenuse?
9 : 25
10
The interesection of A and B.
75:11

24. A number is divisible by 3 if ...
Indeterminable.
Ax^2 + bx + c where a -b and c are constants and a /=0
The sum of its digits is divisible by 3.
8

25. What is the set of elements which can be found in either A or B?
18
61 - 67
The set of elements found in both A and B.
The union of A and B.

26. What are congruent triangles?
The set of output values for a function.
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.
Triangles with same measure and same side lengths.
1.0843 X 10^11

27. a^2 + 2ab + b^2
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
2.592 kg
The set of elements which can be found in either A or B.
(a + b)^2

28. The number of degrees in the largest angle of a triangle inscribed in a circle - in which the diameter of the circle is one side of the triangle.
75:11
An angle which is supplementary to an interior angle.
(a - b)(a + b)
90 degrees

29. a^2 - 2ab + b^2
I
1
(a - b)^2
Infinite.

30. A company places a 6-symbol code on each product. The code consists of the letter T - followed by 3 numerical digits - and then 2 consonants (Y is a conson). How many codes are possible?
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
2sqrt6
The set of output values for a function.
441000 = 1 10 10 10 21 * 21

31. 6w^2 - w - 15 = 0
A = pi(r^2)
A grouping of the members within a set based on a shared characteristic.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
3/2 - 5/3

32. Which is greater? 64^5 or 16^8
Sqrt 12
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
12! / 5!7! = 792
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

33. What is the percent formula?
Part = Percent X Whole
2
1
53 - 59

34. a^0 =
Relationship cannot be determined (what if x is negative?)
1
A set with a number of elements which can be counted.
An arc is a portion of a circumference of a circle.

35. x^4 + x^7 =
x^(4+7) = x^11
1
The interesection of A and B.
Yes - like radicals can be added/subtracted.

36. 25^(1/2) or sqrt. 25 =
Pi is the ratio of a circle'S circumference to its diameter.
Cd
5 OR -5
Angle/360 x 2(pi)r

37. Formula to find a circle'S circumference from its diameter?
An arc is a portion of a circumference of a circle.
48
C = (pi)d
C = 2(pi)r

38. 4.809 X 10^7 =
x^(4+7) = x^11
(p + q)/5
.0004809 X 10^11
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...

39. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
3/2 - 5/3
2 & 3/7
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
70

40. What is the empty set?
62.5%
A set with no members - denoted by a circle with a diagonal through it.
11 - 13 - 17 - 19
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.

41. 8.84 / 5.2
1.7
3sqrt4
I
True

42. Volume for a cylinder?
A circle centered at -2 - -2 with radius 3.
130pi
9 & 6/7
Area of the base X height = (pi)hr^2

43. Simplify 9^(1/2) X 4^3 X 2^(-6)?
12! / 5!7! = 792
3
31 - 37
1/a^6

44. What is the intersection of A and B?
The set of elements found in both A and B.
52
F(x-c)
A reflection about the axis.

45. Legs 5 - 12. Hypotenuse?
13
180 degrees
4.25 - 6 - 22
A circle centered at -2 - -2 with radius 3.

46. Can you simplify sqrt72?
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
12! / 5!7! = 792
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

47. Whats the difference between factors and multiples?
A = pi(r^2)
Factors are few - multiples are many.
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)
55%

48. Which is greater? 200x^295 or 10x^294?
Relationship cannot be determined (what if x is negative?)
12sqrt2
13
2 & 3/7

49. Find the surface area of a cylinder with radius 3 and height 12.
III
72
90pi
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

50. 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?
83.333%
2.592 kg
The interesection of A and B.
From northeast - counterclockwise. I - II - III - IV