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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 number is divisible by 9 if...
The sum of digits is divisible by 9.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
83.333%
Undefined - because we can'T divide by 0.

2. Circumference of a circle?
A chord is a line segment joining two points on a circle.
The union of A and B.
61 - 67
Diameter(Pi)

3. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
From northeast - counterclockwise. I - II - III - IV
(a + b)^2
Cd
The third side is greater than the difference and less than the sum.

4. Volume for a cylinder?
(amount of increase/original price) x 100%
1.7
3
Area of the base X height = (pi)hr^2

5. What are the integers?
The curve opens upward and the vertex is the minimal point on the graph.
All numbers multiples of 1.
Area of the base X height = (pi)hr^2
2 & 3/7

6. To multiply a number by 10^x
Move the decimal point to the right x places
5 OR -5
3/2 - 5/3
A grouping of the members within a set based on a shared characteristic.

7. 3/8 in percent?
37.5%
A reflection about the axis.
The overlapping sections.
Two angles whose sum is 90.

8. Which is greater? 200x^295 or 10x^294?
2sqrt6
48
Relationship cannot be determined (what if x is negative?)
(amount of increase/original price) x 100%

9. 1/6 in percent?
The sum of its digits is divisible by 3.
Undefined - because we can'T divide by 0.
(a + b)^2
16.6666%

10. What is the absolute value function?
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Divide by 100.
The two xes after factoring.
G(x) = {x}

11. 5/8 in percent?
F(x) - c
A tangent is a line that only touches one point on the circumference of a circle.
288 (8 9 4)
62.5%

12. What is the graph of f(x) shifted right c units or spaces?
F(x-c)
A = I (1 + rt)
1
53 - 59

13. The perimeter of a square is 48 inches. The length of its diagonal is:
An expression with just one term (-6x - 2a^2)
3/2 - 5/3
6
12sqrt2

14. What is the name for a grouping of the members within a set based on a shared characteristic?
13pi / 2
0
A subset.
The greatest value minus the smallest.

15. The ratio of the areas of two similar polygons is ...
1/a^6
1
1
... the square of the ratios of the corresponding sides.

16. What is the intersection of A and B?
The set of elements found in both A and B.
413.03 / 10^4 (move the decimal point 4 places to the left)
2(pi)r^2 + 2(pi)rh
2^9 / 2 = 256

17. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
Angle/360 x 2(pi)r
The union of A and B.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
(b + c)

18. When the 'a' in the parabola is negative...
3
Sector area = (n/360) X (pi)r^2
All numbers multiples of 1.
The curve opens downward and the vertex is the maximum point on the graph.

19. What does the graph x^2 + y^2 = 64 look like?
A circle centered on the origin with radius 8.
1
A reflection about the origin.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

20. What is a finite set?
(b + c)
A set with a number of elements which can be counted.
72
A = I (1 + rt)

21. What is the 'domain' of a function?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
F(x) + c
The direction of the inequality is reversed.
The set of input values for a function.

22. How to find the area of a sector?
Part = Percent X Whole
III
Angle/360 x (pi)r^2
20.5

23. Formula to find a circle'S circumference from its radius?
71 - 73 - 79
12.5%
C = 2(pi)r
A reflection about the origin.

24. 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?
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
Two angles whose sum is 180.
72
55%

25. (6sqrt3) x (2sqrt5) =
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
Undefined
3
C = (pi)d

26. Formula for the area of a circle?
413.03 / 10^4 (move the decimal point 4 places to the left)
1
A = pi(r^2)
No - only like radicals can be added.

27. (a^-1)/a^5
A circle centered at -2 - -2 with radius 3.
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.
A subset.
1/a^6

28. What is the empty set?
A set with no members - denoted by a circle with a diagonal through it.
Undefined
180
1

29. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
75:11
G(x) = {x}
Factors are few - multiples are many.
A reflection about the origin.

30. 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?
N! / (k!)(n-k)!
Lies opposite the greater angle
10! / 3!(10-3)! = 120
Infinite.

31. What are congruent triangles?
Triangles with same measure and same side lengths.
The point of intersection of the systems.
When the function is not defined for all real numbers -; only a subset of the real numbers.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

32. Describe the relationship between 3x^2 and 3(x - 1)^2
Two angles whose sum is 180.
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
N! / (k!)(n-k)!
F(x) - c

33. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
(a - b)(a + b)
A circle centered at -2 - -2 with radius 3.
413.03 / 10^4 (move the decimal point 4 places to the left)
71 - 73 - 79

34. The slope of a line perpendicular to (a/b)?
13
The direction of the inequality is reversed.
Its negative reciprocal. (-b/a)
37.5%

35. Factor a^2 + 2ab + b^2
(a + b)^2
83.333%
Triangles with same measure and same side lengths.
1.0843 X 10^11

36. Which is greater? 64^5 or 16^8
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
y = 2x^2 - 3
The set of elements which can be found in either A or B.
7 / 1000

37. Evaluate 4/11 + 11/12
288 (8 9 4)
67 - 71 - 73
52
1 & 37/132

38. What are the rational numbers?
Two angles whose sum is 90.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
A chord is a line segment joining two points on a circle.
...multiply by 100.

39. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
13pi / 2
Divide by 100.
2.592 kg
10

40. 7/8 in percent?
31 - 37
A subset.
130pi
87.5%

41. 6w^2 - w - 15 = 0
180
1.0843 X 10^11
Sqrt 12
3/2 - 5/3

42. Simplify (a^2 + b)^2 - (a^2 - b)^2
(amount of increase/original price) x 100%
180
4a^2(b)
The third side is greater than the difference and less than the sum.

43. What is the 'Restricted domain of a function'?
F(x) + c
When the function is not defined for all real numbers -; only a subset of the real numbers.
The greatest value minus the smallest.
180

44. 5x^2 - 35x -55 = 0
The second graph is less steep.
Ax^2 + bx + c where a -b and c are constants and a /=0
G(x) = {x}
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]

45. What is the maximum value for the function g(x) = (-2x^2) -1?
A 30-60-90 triangle.
1
Pi is the ratio of a circle'S circumference to its diameter.
A = pi(r^2)

46. Convert 0.7% to a fraction.
The curve opens upward and the vertex is the minimal point on the graph.
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
7 / 1000
The set of input values for a function.

47. What is the name of set with a number of elements which cannot be counted?
F(x) - c
An infinite set.
Infinite.
5

48. sqrt 2(sqrt 6)=
The point of intersection of the systems.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
Sqrt 12
Its negative reciprocal. (-b/a)

49. Can the input value of a function have more than one output value (i.e. x: y - y1)?
No - the input value has exactly one output.
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...
Sqrt 12
53 - 59

50. How to find the diagonal of a rectangular solid?
2 & 3/7
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
y = 2x^2 - 3
Divide by 100.