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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 are the smallest three prime numbers greater than 65?
x^(4+7) = x^11
The shortest arc between points A and B on a circle'S diameter.
90 degrees
67 - 71 - 73

2. What is a central angle?
Its last two digits are divisible by 4.
C = (pi)d
When the function is not defined for all real numbers -; only a subset of the real numbers.
A central angle is an angle formed by 2 radii.

3. 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?
1
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
2.592 kg
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.

4. What is the sum of the angles of a triangle?
C = 2(pi)r
75:11
Sector area = (n/360) X (pi)r^2
180 degrees

5. Convert 0.7% to a fraction.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
The point of intersection of the systems.
7 / 1000
Diameter(Pi)

6. Which quadrant is the lower left hand?
x^(2(4)) =x^8 = (x^4)^2
Two angles whose sum is 180.
III
Divide by 100.

7. What is the formula for compounded interest?
20.5
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.
8
F(x + c)

8. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
$11 -448
Yes. [i.e. f(x) = x^2 - 1
Ax^2 + bx + c where a -b and c are constants and a /=0
72

9. What is the maximum value for the function g(x) = (-2x^2) -1?
1
Divide by 100.
The two xes after factoring.
Cd

10. What is the surface area of a cylinder with radius 5 and height 8?
130pi
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
A reflection about the axis.
288 (8 9 4)

11. What number between 70 & 75 - inclusive - has the greatest number of factors?
(a - b)^2
72
(base*height) / 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)

12. 10^6 has how many zeroes?
The set of elements which can be found in either A or B.
F(x) + c
(base*height) / 2
6

13. What is the slope of a vertical line?

14. 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?
y = 2x^2 - 3
90pi
2(pi)r^2 + 2(pi)rh
83.333%

15. What is the set of elements which can be found in either A or B?
28. n = 8 - k = 2. n! / k!(n-k)!
The union of A and B.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
1

16. What is a tangent?
x(x - y + 1)
A tangent is a line that only touches one point on the circumference of a circle.
All numbers multiples of 1.
C = (pi)d

17. A number is divisible by 9 if...
Angle/360 x (pi)r^2
x(x - y + 1)
The sum of digits is divisible by 9.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

18. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
12.5%
The steeper the slope.
28. n = 8 - k = 2. n! / k!(n-k)!
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

19. Formula to find a circle'S circumference from its radius?
The sum of its digits is divisible by 3.
1
An arc is a portion of a circumference of a circle.
C = 2(pi)r

20. 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?
130pi
x^(4+7) = x^11
N! / (k!)(n-k)!
F(x) - c

21. What is the graph of f(x) shifted downward c units or spaces?
From northeast - counterclockwise. I - II - III - IV
(a - b)(a + b)
F(x) - c
No - the input value has exactly one output.

22. What are the integers?
1
All numbers multiples of 1.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
28. n = 8 - k = 2. n! / k!(n-k)!

23. 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?
Cd
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
441000 = 1 10 10 10 21 * 21
The sum of digits is divisible by 9.

24. What is the formula for computing simple interest?
A = I (1 + rt)
9 : 25
True
x^(4+7) = x^11

25. What percent of 40 is 22?
90 degrees
The sum of its digits is divisible by 3.
1
55%

26. Write 10 -843 X 10^7 in scientific notation
Its negative reciprocal. (-b/a)
(a + b)^2
Its divisible by 2 and by 3.
1.0843 X 10^11

27. x^2 = 9. What is the value of x?
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
A = pi(r^2)
3 - -3
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

28. Circumference of a circle?
Diameter(Pi)
All numbers multiples of 1.
1:sqrt3:2
180 degrees

29. Legs 6 - 8. Hypotenuse?
71 - 73 - 79
1
10
Indeterminable.

30. x^6 / x^3
The sum of digits is divisible by 9.
1:sqrt3:2
x^(6-3) = x^3
(amount of decrease/original price) x 100%

31. 60 < all primes <70
61 - 67
Part = Percent X Whole
6 : 1 : 2
G(x) = {x}

32. Find the surface area of a cylinder with radius 3 and height 12.
Members or elements
C = (pi)d
IV
90pi

33. 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.
(a + b)^2
(p + q)/5
The sum of digits is divisible by 9.

34. Simplify 9^(1/2) X 4^3 X 2^(-6)?
20.5
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
3
12sqrt2

35. What is the absolute value function?
2(pi)r^2 + 2(pi)rh
12.5%
G(x) = {x}
Sqrt 12

36. Can you simplify sqrt72?
1
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
9 & 6/7
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

37. 6w^2 - w - 15 = 0
Undefined - because we can'T divide by 0.
3/2 - 5/3
1.0843 X 10^11
27^(-4)

38. Which quadrant is the upper right hand?
Ax^2 + bx + c where a -b and c are constants and a /=0
0
F(x + c)
I

39. 70 < all primes< 80
A central angle is an angle formed by 2 radii.
62.5%
An arc is a portion of a circumference of a circle.
71 - 73 - 79

40. What is the slope of a horizontal line?
2sqrt6
(amount of increase/original price) x 100%
0
The overlapping sections.

41. P and r are factors of 100. What is greater - pr or 100?
Indeterminable.
1.0843 X 10^11
4.25 - 6 - 22
F(x) + c

42. What is an isoceles triangle?
Two angles whose sum is 90.
Two equal sides and two equal angles.
A reflection about the origin.
C = 2(pi)r

43. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
12sqrt2
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
83.333%
70

44. What is the 'domain' of a function?
4096
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
N! / (n-k)!
The set of input values for a function.

45. What are the members or elements of a set?
C = (pi)d
1
The objects within a set.
130pi

46. When the 'a' in a parabola is positive....
The curve opens upward and the vertex is the minimal point on the graph.
180 degrees
The set of elements which can be found in either A or B.
(p + q)/5

47. 5 bakeries sell an average of 300 muffins per bakery per day. If 2 stop making muffins but the total muffins sold stays the same - what is the average of muffins per bakery sold among the remaining?
1
A subset.
500
The set of elements which can be found in either A or B.

48. The objects in a set are called two names:
13pi / 2
6 : 1 : 2
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
Members or elements

49. What is the measure of an exterior angle of a regular pentagon?
(amount of increase/original price) x 100%
72
True
F(x + c)

50. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
1
90pi
13pi / 2
3