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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. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
13pi / 2
1/a^6
3
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

2. 40 < all primes<50
288 (8 9 4)
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
4.25 - 6 - 22
41 - 43 - 47

3. How many 3-digit positive integers are even and do not contain the digit 4?
4725
288 (8 9 4)
N! / (k!)(n-k)!
The overlapping sections.

4. What percent of 40 is 22?
A = I (1 + rt)
55%
Its divisible by 2 and by 3.
180

5. Formula to find a circle'S circumference from its radius?
C = 2(pi)r
75:11
The objects within a set.
True

6. 3/8 in percent?
37.5%
Yes. [i.e. f(x) = x^2 - 1
A set with no members - denoted by a circle with a diagonal through it.
12sqrt2

7. What are the real numbers?
(a - b)^2
(b + c)
(a - b)(a + b)
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. What is the set of elements which can be found in either A or B?
13
Two angles whose sum is 180.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
The union of A and B.

9. 2sqrt4 + sqrt4 =
x= (1.2)(.8)lw
90
The greatest value minus the smallest.
3sqrt4

10. What are the smallest three prime numbers greater than 65?
67 - 71 - 73
1/(x^y)
62.5%
Ax^2 + bx + c where a -b and c are constants and a /=0

11. What is an isoceles triangle?
5
71 - 73 - 79
Two equal sides and two equal angles.
The empty set - denoted by a circle with a diagonal through it.

12. What are the roots of the quadrinomial x^2 + 2x + 1?
F(x) - c
The two xes after factoring.
1
II

13. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
An isosceles right triangle.
$3 -500 in the 9% and $2 -500 in the 7%.
500
6

14. Describe the relationship between 3x^2 and 3(x - 1)^2
7 / 1000
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
The set of output values for a function.

15. What is the graph of f(x) shifted right c units or spaces?
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
1
1/a^6
F(x-c)

16. What is the slope of a horizontal line?
0
x^(4+7) = x^11
Indeterminable.
6

17. What is the 'Range' of a function?
Sector area = (n/360) X (pi)r^2
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
The set of output values for a function.
3 - -3

18. What is a subset?
A grouping of the members within a set based on a shared characteristic.
III
A reflection about the axis.
(amount of decrease/original price) x 100%

19. Whats the difference between factors and multiples?
Even
Factors are few - multiples are many.
53 - 59
441000 = 1 10 10 10 21 * 21

20. Length of an arc of a circle?
Angle/360 x 2(pi)r
$11 -448
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
(a - b)^2

21. 413.03 x 10^(-4) =
413.03 / 10^4 (move the decimal point 4 places to the left)
(amount of decrease/original price) x 100%
Its divisible by 2 and by 3.
F(x) + c

22. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
2^9 / 2 = 256
Yes. [i.e. f(x) = x^2 - 1
10! / (10-3)! = 720
53 - 59

23. Simplify 9^(1/2) X 4^3 X 2^(-6)?
10
The empty set - denoted by a circle with a diagonal through it.
12sqrt2
3

24. Which is greater? 64^5 or 16^8
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
Factors are few - multiples are many.
No - only like radicals can be added.
An expression with just one term (-6x - 2a^2)

25. Order of quadrants:
(a + b)^2
From northeast - counterclockwise. I - II - III - IV
$3 -500 in the 9% and $2 -500 in the 7%.
An angle which is supplementary to an interior angle.

26. If the two sides of a triangle are unequal then the longer side...
Lies opposite the greater angle
F(x-c)
1:1:sqrt2
Pi is the ratio of a circle'S circumference to its diameter.

27. Is 0 even or odd?
Even
Factors are few - multiples are many.
67 - 71 - 73
(a + b)^2

28. What is a finite set?
90
Two equal sides and two equal angles.
The curve opens downward and the vertex is the maximum point on the graph.
A set with a number of elements which can be counted.

29. Which quandrant is the lower right hand?
A circle centered on the origin with radius 8.
IV
23 - 29
Indeterminable.

30. x^4 + x^7 =
10! / 3!(10-3)! = 120
x^(4+7) = x^11
No - only like radicals can be added.
A circle centered on the origin with radius 8.

31. 10^6 has how many zeroes?
The two xes after factoring.
6
90 degrees
12! / 5!7! = 792

32. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
16.6666%
3 - -3
2
3/2 - 5/3

33. What is the empty set?
72
(amount of decrease/original price) x 100%
(base*height) / 2
A set with no members - denoted by a circle with a diagonal through it.

34. How to find the area of a sector?
The overlapping sections.
1
Its last two digits are divisible by 4.
Angle/360 x (pi)r^2

35. Formula to find a circle'S circumference from its diameter?
The greatest value minus the smallest.
Part = Percent X Whole
Yes - like radicals can be added/subtracted.
C = (pi)d

36. 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?
C = (pi)d
9 : 25
413.03 / 10^4 (move the decimal point 4 places to the left)
No - the input value has exactly one output.

37. What is the graph of f(x) shifted downward c units or spaces?
1.0843 X 10^11
F(x) - c
1/2 times 7/3
The greatest value minus the smallest.

38. What transformation occurs if point C is reflected over the x-axis and then the y-axis?
180
20.5
A reflection about the axis.
1/2 times 7/3

39. Factor x^2 - xy + x.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
The set of elements which can be found in either A or B.
70
x(x - y + 1)

40. 30< all primes<40
x= (1.2)(.8)lw
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
31 - 37
$3 -500 in the 9% and $2 -500 in the 7%.

41. 25^(1/2) or sqrt. 25 =
48
x^(4+7) = x^11
9 & 6/7
5 OR -5

42. 0^0
Factors are few - multiples are many.
Undefined
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
9 & 6/7

43. a^0 =
1
C = (pi)d
x^(2(4)) =x^8 = (x^4)^2
A subset.

44. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
Infinite.
2sqrt6
Triangles with same measure and same side lengths.
The curve opens downward and the vertex is the maximum point on the graph.

45. Which is greater? 200x^295 or 10x^294?
An angle which is supplementary to an interior angle.
Members or elements
3 - -3
Relationship cannot be determined (what if x is negative?)

46. Find the surface area of a cylinder with radius 3 and height 12.
An angle which is supplementary to an interior angle.
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
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)
90pi

47. (-1)^3 =
Two angles whose sum is 180.
A grouping of the members within a set based on a shared characteristic.
The union of A and B.
1

48. 60 < all primes <70
A set with a number of elements which can be counted.
61 - 67
Undefined - because we can'T divide by 0.
9 & 6/7

49. How many multiples does a given number have?
9 : 25
Infinite.
1:1:sqrt2
III

50. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
2(pi)r^2 + 2(pi)rh
Cd
1
53 - 59