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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. 1/8 in percent?
IV
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
(base*height) / 2
12.5%

2. Length of an arc of a circle?
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
7 / 1000
A = I (1 + rt)
Angle/360 x 2(pi)r

3. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
x= (1.2)(.8)lw
71 - 73 - 79
12! / 5!7! = 792
1

4. Define a 'Term' -
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
The curve opens upward and the vertex is the minimal point on the graph.
A subset.
x^(4+7) = x^11

5. 25^(1/2) or sqrt. 25 =
5 OR -5
180 degrees
Sqrt 12
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

6. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
(a + b)^2
3
Factors are few - multiples are many.
72

7. Simplify the expression (p^2 - q^2)/ -5(q - p)
9 & 6/7
(p + q)/5
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
1/(x^y)

8. If the 80th percentile of the measurements is 72degrees - about how many measurments are between 69 degrees and 72 degrees? Round your answer to the nearest tenth
N! / (k!)(n-k)!
18
10! / 3!(10-3)! = 120
The sum of digits is divisible by 9.

9. Can the input value of a function have more than one output value (i.e. x: y - y1)?
III
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
No - the input value has exactly one output.
1:1:sqrt2

10. If the two sides of a triangle are unequal then the longer side...
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
The empty set - denoted by a circle with a diagonal through it.
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
Lies opposite the greater angle

11. What is a set with no members called?
288 (8 9 4)
.0004809 X 10^11
The empty set - denoted by a circle with a diagonal through it.
Undefined - because we can'T divide by 0.

12. Employee X is paid 19.50 per hour no matter how many a week. Employee Y earns 18 for the first 40 and 1.5 the hourly wage for every hour after that. If both earned the same amount and worked the same in one week - how many did each work?
A grouping of the members within a set based on a shared characteristic.
2.592 kg
48
2^9 / 2 = 256

13. sqrt 2(sqrt 6)=
55%
x^(6-3) = x^3
III
Sqrt 12

14. a^2 - 2ab + b^2
A circle centered on the origin with radius 8.
Yes. [i.e. f(x) = x^2 - 1
(a - b)^2
An angle which is supplementary to an interior angle.

15. How to find the diagonal of a rectangular solid?
Two equal sides and two equal angles.
An expression with just one term (-6x - 2a^2)
Its last two digits are divisible by 4.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

16. 20<all primes<30
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
The longest arc between points A and B on a circle'S diameter.
An angle which is supplementary to an interior angle.
23 - 29

17. 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?
F(x) - c
(a + b)^2
$11 -448
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

18. Can you simplify sqrt72?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
Members or elements
The set of elements found in both A and B.
7 / 1000

19. What is the intersection of A and B?
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
F(x) + c
N! / (k!)(n-k)!
The set of elements found in both A and B.

20. Circumference of a circle?
Diameter(Pi)
1:1:sqrt2
87.5%
20.5

21. x^4 + x^7 =
Lies opposite the greater angle
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...
C = 2(pi)r
x^(4+7) = x^11

22. What is the 'Range' of a series of numbers?
2sqrt6
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
The greatest value minus the smallest.
1:1:sqrt2

23. Max and Min lengths for a side of a triangle?
The third side is greater than the difference and less than the sum.
Diameter(Pi)
A chord is a line segment joining two points on a circle.
A = pi(r^2)

24. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
x^(2(4)) =x^8 = (x^4)^2
4725
41 - 43 - 47
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)

25. What are the members or elements of a set?
The objects within a set.
F(x-c)
The second graph is less steep.
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)

26. What is an exterior angle?
Two angles whose sum is 90.
An angle which is supplementary to an interior angle.
The overlapping sections.
0

27. x^(-y)=
A subset.
37.5%
1/(x^y)
4a^2(b)

28. What are complementary angles?
Two angles whose sum is 90.
The interesection of A and B.
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
An expression with just one term (-6x - 2a^2)

29. Legs 5 - 12. Hypotenuse?
Even
31 - 37
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
13

30. What is a chord of a circle?
A chord is a line segment joining two points on a circle.
16.6666%
2.592 kg
7 / 1000

31. In a regular polygon with n sides - the formula for the sum of interior angles
(a - b)(a + b)
Two angles whose sum is 180.
(n-2) x 180
A set with a number of elements which can be counted.

32. What is the graph of f(x) shifted upward c units or spaces?
13
A chord is a line segment joining two points on a circle.
Divide by 100.
F(x) + c

33. Write 10 -843 X 10^7 in scientific notation
1.0843 X 10^11
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
Infinite.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

34. What is the name for a grouping of the members within a set based on a shared characteristic?
A subset.
72
55%
12.5%

35. 5x^2 - 35x -55 = 0
180
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
(a + b)^2
$3 -500 in the 9% and $2 -500 in the 7%.

36. 413.03 x 10^(-4) =
Indeterminable.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
413.03 / 10^4 (move the decimal point 4 places to the left)
An expression with just one term (-6x - 2a^2)

37. When the 'a' in a parabola is positive....
2sqrt6
The curve opens upward and the vertex is the minimal point on the graph.
Two angles whose sum is 90.
4725

38. Formula to find a circle'S circumference from its radius?
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)
C = 2(pi)r
The curve opens downward and the vertex is the maximum point on the graph.
8

39. 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?
11 - 13 - 17 - 19
1
13pi / 2
N! / (k!)(n-k)!

40. x^2 = 9. What is the value of x?
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
Relationship cannot be determined (what if x is negative?)
67 - 71 - 73
3 - -3

41. What are the real numbers?
2 & 3/7
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)
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
An isosceles right triangle.

42. Can you subtract 3sqrt4 from sqrt4?
(amount of increase/original price) x 100%
Yes - like radicals can be added/subtracted.
Yes. [i.e. f(x) = x^2 - 1
75:11

43. (a^-1)/a^5
The third side is greater than the difference and less than the sum.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
1/a^6
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)

44. 8.84 / 5.2
1.7
A grouping of the members within a set based on a shared characteristic.
y = 2x^2 - 3
1:sqrt3:2

45. 10^6 has how many zeroes?
The objects within a set.
6
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
A circle centered on the origin with radius 8.

46. 0^0
Sector area = (n/360) X (pi)r^2
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
Indeterminable.
Undefined

47. 3/8 in percent?
37.5%
1 & 37/132
I
6 : 1 : 2

48. Which is greater? 27^(-4) or 9^(-8)
62.5%
31 - 37
27^(-4)
3/2 - 5/3

49. a^0 =
1
31 - 37
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
The point of intersection of the systems.

50. Factor x^2 - xy + x.
87.5%
9 & 6/7
3
x(x - y + 1)