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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 is the graph of f(x) shifted downward c units or spaces?
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
F(x) - c
Diameter(Pi)
A subset.

2. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
Members or elements
A reflection about the origin.
Two equal sides and two equal angles.
The second graph is less steep.

3. 1/2 divided by 3/7 is the same as
A chord is a line segment joining two points on a circle.
1/2 times 7/3
48
(a - b)(a + b)

4. Formula for the area of a sector of a circle?
C = 2(pi)r
Sector area = (n/360) X (pi)r^2
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...
A set with a number of elements which can be counted.

5. (12sqrt15) / (2sqrt5) =
(a - b)^2
The union of A and B.
The longest arc between points A and B on a circle'S diameter.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

6. What is the ratio of the sides of a 30-60-90 triangle?
1:sqrt3:2
87.5%
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

7. Define an 'expression'.
83.333%
A reflection about the axis.
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)
No - only like radicals can be added.

8. A number is divisible by 6 if...
Part = Percent X Whole
A circle centered at -2 - -2 with radius 3.
(base*height) / 2
Its divisible by 2 and by 3.

9. x^4 + x^7 =
90
x^(4+7) = x^11
7 / 1000
1.7

10. What are 'Supplementary angles?'
Two angles whose sum is 180.
180
Its divisible by 2 and by 3.
18

11. 4.809 X 10^7 =
A central angle is an angle formed by 2 radii.
.0004809 X 10^11
3sqrt4
130pi

12. What is the slope of a vertical line?

13. How to find the diagonal of a rectangular solid?
48
Sector area = (n/360) X (pi)r^2
1
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

14. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
9 & 6/7
A = pi(r^2)
Area of the base X height = (pi)hr^2
90

15. 40 < all primes<50
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
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)
41 - 43 - 47
...multiply by 100.

16. Describe the relationship between the graphs of x^2 and (1/2)x^2
288 (8 9 4)
The second graph is less steep.
Lies opposite the greater angle
20.5

17. What is the ratio of the sides of an isosceles right triangle?
The direction of the inequality is reversed.
130pi
The set of input values for a function.
1:1:sqrt2

18. 2sqrt4 + sqrt4 =
3sqrt4
6
Area of the base X height = (pi)hr^2
62.5%

19. 5/8 in percent?
62.5%
A = pi(r^2)
A grouping of the members within a set based on a shared characteristic.
27^(-4)

20. What is the 'Restricted domain of a function'?
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
When the function is not defined for all real numbers -; only a subset of the real numbers.
A circle centered on the origin with radius 8.
90

21. What is the name for a grouping of the members within a set based on a shared characteristic?
Sqrt 12
The objects within a set.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
A subset.

22. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
2^9 / 2 = 256
(a + b)^2
2sqrt6
IV

23. What is a set with no members called?
x^(6-3) = x^3
1:sqrt3:2
6 : 1 : 2
The empty set - denoted by a circle with a diagonal through it.

24. Which is greater? 64^5 or 16^8
C = (pi)d
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
500

25. 50 < all primes< 60
4.25 - 6 - 22
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
83.333%
53 - 59

26. What is a parabola?
Pi is the ratio of a circle'S circumference to its diameter.
Ax^2 + bx + c where a -b and c are constants and a /=0
1 & 37/132
The curve opens upward and the vertex is the minimal point on the graph.

27. What is the set of elements which can be found in either A or B?
Undefined
The union of A and B.
9 : 25
1

28. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
A grouping of the members within a set based on a shared characteristic.
No - the input value has exactly one output.
I
8

29. (x^2)^4
A set with a number of elements which can be counted.
x^(2(4)) =x^8 = (x^4)^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.
F(x-c)

30. Formula to calculate arc length?
180
y = 2x^2 - 3
10! / 3!(10-3)! = 120
Arc length = (n/360) x pi(2r) where n is the number of degrees.

31. Evaluate (4^3)^2
(a - b)(a + b)
4096
90 degrees
1/2 times 7/3

32. What are the real numbers?
Factors are few - multiples are many.
Area of the base X height = (pi)hr^2
The steeper the slope.
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)

33. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
4725
2 & 3/7
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.
True

34. What is a chord of a circle?
A chord is a line segment joining two points on a circle.
5
41 - 43 - 47
Area of the base X height = (pi)hr^2

35. Simplify the expression [(b^2 - c^2) / (b - c)]
10! / (10-3)! = 720
The sum of its digits is divisible by 3.
Part = Percent X Whole
(b + c)

36. What is the surface area of a cylinder with radius 5 and height 8?
A = pi(r^2)
...multiply by 100.
90 degrees
130pi

37. Legs 6 - 8. Hypotenuse?
52
Move the decimal point to the right x places
A 30-60-90 triangle.
10

38. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
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)
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
2 & 3/7
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...

39. The larger the absolute value of the slope...
N! / (n-k)!
The steeper the slope.
x^(2(4)) =x^8 = (x^4)^2
12! / 5!7! = 792

40. How many multiples does a given number have?
Undefined - because we can'T divide by 0.
Infinite.
A central angle is an angle formed by 2 radii.
4:5

41. How to determine percent decrease?
Even
No - the input value has exactly one output.
55%
(amount of decrease/original price) x 100%

42. 5/6 in percent?
83.333%
A subset.
A circle centered on the origin with radius 8.
90 degrees

43. Simplify (a^2 + b)^2 - (a^2 - b)^2
2(pi)r^2 + 2(pi)rh
4a^2(b)
Cd
Indeterminable.

44. What is a tangent?
The greatest value minus the smallest.
The interesection of A and B.
A tangent is a line that only touches one point on the circumference of a circle.
83.333%

45. Can you simplify sqrt72?
The set of elements found in both A and B.
A set with no members - denoted by a circle with a diagonal through it.
180
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

46. Order of quadrants:
A chord is a line segment joining two points on a circle.
3 - -3
Undefined
From northeast - counterclockwise. I - II - III - IV

47. Surface area for a cylinder?
2(pi)r^2 + 2(pi)rh
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
16.6666%
A tangent is a line that only touches one point on the circumference of a circle.

48. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
55%
75:11
A 30-60-90 triangle.
A = pi(r^2)

49. What is the 'Range' of a series of numbers?
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...
Infinite.
The greatest value minus the smallest.
72

50. What is the name of set with a number of elements which cannot be counted?
Infinite.
Undefined - because we can'T divide by 0.
Sector area = (n/360) X (pi)r^2
An infinite set.