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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 does scientific notation mean?
Divide by 100.
75:11
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
12! / 5!7! = 792

2. 50 < all primes< 60
0
53 - 59
1 & 37/132
(a - b)^2

3. x^4 + x^7 =
The set of elements found in both A and B.
Sector area = (n/360) X (pi)r^2
28. n = 8 - k = 2. n! / k!(n-k)!
x^(4+7) = x^11

4. What is a tangent?
A tangent is a line that only touches one point on the circumference of a circle.
A set with a number of elements which can be counted.
Sqrt 12
x= (1.2)(.8)lw

5. What is the set of elements found in both A and B?
Its negative reciprocal. (-b/a)
1 & 37/132
The interesection of A and B.
2^9 / 2 = 256

6. Legs 5 - 12. Hypotenuse?
Angle/360 x (pi)r^2
27^(-4)
9 & 6/7
13

7. To convert a percent to a fraction....
75:11
61 - 67
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...
Divide by 100.

8. What is the set of elements which can be found in either A or B?
71 - 73 - 79
83.333%
The union of A and B.
(p + q)/5

9. What is a subset?
A grouping of the members within a set based on a shared characteristic.
When the function is not defined for all real numbers -; only a subset of the real numbers.
13
The two xes after factoring.

10. Write 10 -843 X 10^7 in scientific notation
1.0843 X 10^11
Infinite.
A circle centered at -2 - -2 with radius 3.
1

11. Legs: 3 - 4. Hypotenuse?
Undefined
5
An infinite set.
Two angles whose sum is 90.

12. The objects in a set are called two names:
1 & 37/132
2.592 kg
Members or elements
10

13. 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?
An infinite set.
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)
2.592 kg
(b + c)

14. Can you add sqrt 3 and sqrt 5?
413.03 / 10^4 (move the decimal point 4 places to the left)
18
No - only like radicals can be added.
y = 2x^2 - 3

15. Define a 'monomial'
$11 -448
(a - b)^2
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
An expression with just one term (-6x - 2a^2)

16. 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?
Indeterminable.
16.6666%
9 : 25
The curve opens downward and the vertex is the maximum point on the graph.

17. Which is greater? 64^5 or 16^8
An infinite set.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
2sqrt6
G(x) = {x}

18. What is the percent formula?
2sqrt6
(a + b)^2
3
Part = Percent X Whole

19. A cylinder has a surface area of 22pi. If the cylinder has a height of 10 - what is the radius?
The overlapping sections.
Its negative reciprocal. (-b/a)
(amount of increase/original price) x 100%
1

20. Can you simplify sqrt72?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
C = (pi)d
28. n = 8 - k = 2. n! / k!(n-k)!
1:sqrt3:2

21. What number between 70 & 75 - inclusive - has the greatest number of factors?
72
The point of intersection of the systems.
A set with no members - denoted by a circle with a diagonal through it.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

22. 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?
x^(6-3) = x^3
(amount of increase/original price) x 100%
10! / 3!(10-3)! = 120
413.03 / 10^4 (move the decimal point 4 places to the left)

23. What is the 'Range' of a function?
A = I (1 + rt)
31 - 37
The set of output values for a function.
C = (pi)d

24. How to determine percent increase?
An isosceles right triangle.
130pi
(amount of increase/original price) x 100%
A chord is a line segment joining two points on a circle.

25. 10^6 has how many zeroes?
6
The shortest arc between points A and B on a circle'S diameter.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
1/(x^y)

26. What is the graph of f(x) shifted left c units or spaces?
83.333%
F(x + c)
5 OR -5
The longest arc between points A and B on a circle'S diameter.

27. How many multiples does a given number have?
61 - 67
Infinite.
1
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

28. x^2 = 9. What is the value of x?
Lies opposite the greater angle
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
No - only like radicals can be added.
3 - -3

29. 8.84 / 5.2
1.7
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
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...
The curve opens upward and the vertex is the minimal point on the graph.

30. Pi is a ratio of what to what?

31. The perimeter of a square is 48 inches. The length of its diagonal is:
12sqrt2
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
True
2^9 / 2 = 256

32. What is an arc of a circle?
An arc is a portion of a circumference of a circle.
61 - 67
1:sqrt3:2
The sum of digits is divisible by 9.

33. 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?
6 : 1 : 2
441000 = 1 10 10 10 21 * 21
20.5
1:1:sqrt2

34. What are congruent triangles?
31 - 37
A set with no members - denoted by a circle with a diagonal through it.
Triangles with same measure and same side lengths.
Pi is the ratio of a circle'S circumference to its diameter.

35. Define a 'Term' -
2^9 / 2 = 256
52
Triangles with same measure and same side lengths.
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)

36. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
1/2 times 7/3
A 30-60-90 triangle.
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)
8

37. (12sqrt15) / (2sqrt5) =
Two equal sides and two equal angles.
12.5%
(amount of decrease/original price) x 100%
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

38. 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?
.0004809 X 10^11
N! / (k!)(n-k)!
II
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

39. Max and Min lengths for a side of a triangle?
True
A central angle is an angle formed by 2 radii.
The third side is greater than the difference and less than the sum.
41 - 43 - 47

40. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
From northeast - counterclockwise. I - II - III - IV
8
The sum of digits is divisible by 9.
A reflection about the axis.

41. What is the name for a grouping of the members within a set based on a shared characteristic?
12sqrt2
A subset.
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)
(base*height) / 2

42. 70 < all primes< 80
20.5
71 - 73 - 79
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
(n-2) x 180

43. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
90
An arc is a portion of a circumference of a circle.
13
48

44. 5/8 in percent?
2
F(x + c)
62.5%
C = (pi)d

45. 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?
All numbers multiples of 1.
An expression with just one term (-6x - 2a^2)
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
The shortest arc between points A and B on a circle'S diameter.

46. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
Its last two digits are divisible by 4.
Undefined - because we can'T divide by 0.
1/2 times 7/3
2sqrt6

47. Order of quadrants:
C = (pi)d
From northeast - counterclockwise. I - II - III - IV
67 - 71 - 73
III

48. What is a major arc?

49. P and r are factors of 100. What is greater - pr or 100?
75:11
11 - 13 - 17 - 19
(a + b)^2
Indeterminable.

50. How to find the circumference of a circle which circumscribes a square?
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
6
13
18