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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. 40 < all primes<50
x= (1.2)(.8)lw
The set of elements found in both A and B.
41 - 43 - 47
(a - b)^2

2. Which quadrant is the lower left hand?
III
23 - 29
(a - b)(a + b)
(a - b)(a + b)

3. What is the surface area of a cylinder with radius 5 and height 8?
Area of the base X height = (pi)hr^2
All numbers multiples of 1.
130pi
11 - 13 - 17 - 19

4. The objects in a set are called two names:
41 - 43 - 47
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
A grouping of the members within a set based on a shared characteristic.
Members or elements

5. Which is greater? 200x^295 or 10x^294?
Relationship cannot be determined (what if x is negative?)
A subset.
10
2(pi)r^2 + 2(pi)rh

6. (-1)^3 =
$11 -448
288 (8 9 4)
A reflection about the origin.
1

7. A number is divisible by 3 if ...
The sum of its digits is divisible by 3.
A reflection about the axis.
Diameter(Pi)
67 - 71 - 73

8. 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))?
55%
20.5
Undefined - because we can'T divide by 0.
N! / (n-k)!

9. a^2 + 2ab + b^2
Triangles with same measure and same side lengths.
(a + b)^2
True
67 - 71 - 73

10. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
Lies opposite the greater angle
An isosceles right triangle.
Sqrt 12
(b + c)

11. Define an 'expression'.
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)
A chord is a line segment joining two points on a circle.
180 degrees
28. n = 8 - k = 2. n! / k!(n-k)!

12. What are 'Supplementary angles?'
Two angles whose sum is 180.
Even
41 - 43 - 47
Two angles whose sum is 90.

13. What are the rational numbers?
The set of elements found in both A and B.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
72
The point of intersection of the systems.

14. What is a chord of a circle?
9 & 6/7
(amount of decrease/original price) x 100%
A chord is a line segment joining two points on a circle.
Even

15. Max and Min lengths for a side of a triangle?
The third side is greater than the difference and less than the sum.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
.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...

16. sqrt 2(sqrt 6)=
An expression with just one term (-6x - 2a^2)
Sqrt 12
Infinite.
4.25 - 6 - 22

17. What transformation occurs if point C is reflected over the x-axis and then the y-axis?
III
A reflection about the axis.
(a - b)^2
From northeast - counterclockwise. I - II - III - IV

18. The larger the absolute value of the slope...
True
The steeper the slope.
A central angle is an angle formed by 2 radii.
5 OR -5

19. What is the order of operations?
From northeast - counterclockwise. I - II - III - IV
1/a^6
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
A 30-60-90 triangle.

20. When the 'a' in a parabola is positive....
12.5%
70
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)
The curve opens upward and the vertex is the minimal point on the graph.

21. What is the side length of an equilateral triangle with altitude 6?
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...
Even
6
1

22. What is a finite set?
A set with a number of elements which can be counted.
130pi
The two xes after factoring.
Indeterminable.

23. 0^0
Undefined
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
II
2sqrt6

24. 20<all primes<30
23 - 29
Members or elements
83.333%
4096

25. The perimeter of a square is 48 inches. The length of its diagonal is:
1
5 OR -5
4.25 - 6 - 22
12sqrt2

26. What does scientific notation mean?
$11 -448
10
Sqrt 12
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

27. A number is divisible by 4 is...
Its last two digits are divisible by 4.
6 : 1 : 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.
The greatest value minus the smallest.

28. If r - t - s & u are distinct - consecutive prime numbers - less than 31 - which of the following could be an average of them (4 - 4.25 - 6 - 9 - 24 - 22 - 24)
3 - -3
90
4.25 - 6 - 22
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)

29. Formula to find a circle'S circumference from its diameter?
.0004809 X 10^11
C = (pi)d
(a + b)^2
True

30. 60 < all primes <70
...multiply by 100.
61 - 67
Cd
4096

31. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
3 - -3
Sector area = (n/360) X (pi)r^2
18
2^9 / 2 = 256

32. 5/6 in percent?
Sector area = (n/360) X (pi)r^2
1:sqrt3:2
83.333%
F(x-c)

33. 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.
No - only like radicals can be added.
3
90 degrees
3/2 - 5/3

34. Which quadrant is the upper left hand?
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 - like radicals can be added/subtracted.
II
The second graph is less steep.

35. Area of a triangle?
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
(a + b)^2
1:sqrt3:2
(base*height) / 2

36. What are complementary angles?
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
18
Two angles whose sum is 90.
Area of the base X height = (pi)hr^2

37. Legs: 3 - 4. Hypotenuse?
The third side is greater than the difference and less than the sum.
5
A subset.
90

38. Solve the quadratic equation ax^2 + bx + c= 0
Angle/360 x (pi)r^2
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
The union of A and B.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

39. Which is greater? 64^5 or 16^8
The sum of digits is divisible by 9.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
A subset.
A 30-60-90 triangle.

40. What number between 70 & 75 - inclusive - has the greatest number of factors?
72
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.
No - the input value has exactly one output.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

41. The ratio of the areas of two similar polygons is ...
Undefined
1/a^6
... the square of the ratios of the corresponding sides.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

42. How to find the area of a sector?
Divide by 100.
Angle/360 x (pi)r^2
18
1:1:sqrt2

43. What is the formula for compounded interest?
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.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
Lies opposite the greater angle
8

44. How many multiples does a given number have?
18
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)
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
Infinite.

45. x^4 + x^7 =
1/a^6
(n-2) x 180
x^(4+7) = x^11
0

46. A number is divisible by 9 if...
48
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
(base*height) / 2
The sum of digits is divisible by 9.

47. What is an exterior angle?
4:5
The direction of the inequality is reversed.
y = (x + 5)/2
An angle which is supplementary to an interior angle.

48. What is the graph of f(x) shifted downward c units or spaces?
F(x) - c
Pi is the ratio of a circle'S circumference to its diameter.
4725
2.592 kg

49. What is the absolute value function?
The shortest arc between points A and B on a circle'S diameter.
G(x) = {x}
Relationship cannot be determined (what if x is negative?)
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

50. Convert 0.7% to a fraction.
90
180 degrees
16.6666%
7 / 1000