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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 'Range' of a series of numbers?
$11 -448
A subset.
The greatest value minus the smallest.
52

2. When the 'a' in a parabola is positive....
The curve opens upward and the vertex is the minimal point on the graph.
87.5%
20.5
1

3. 2sqrt4 + sqrt4 =
When the function is not defined for all real numbers -; only a subset of the real numbers.
2^9 / 2 = 256
3sqrt4
4a^2(b)

4. What is the order of operations?
1:sqrt3:2
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
20.5
x^(4+7) = x^11

5. The perimeter of a square is 48 inches. The length of its diagonal is:
A 30-60-90 triangle.
13
... the square of the ratios of the corresponding sides.
12sqrt2

6. What is the graph of f(x) shifted upward c units or spaces?
Its negative reciprocal. (-b/a)
2(pi)r^2 + 2(pi)rh
6
F(x) + c

7. What is the 'union' of A and B?
x^(6-3) = x^3
130pi
The two xes after factoring.
The set of elements which can be found in either A or B.

8. x^6 / x^3
A 30-60-90 triangle.
x^(6-3) = x^3
12! / 5!7! = 792
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]

9. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
The curve opens upward and the vertex is the minimal point on the graph.
13pi / 2
180 degrees
II

10. 50 < all primes< 60
II
53 - 59
Angle/360 x (pi)r^2
Diameter(Pi)

11. Legs 5 - 12. Hypotenuse?
1
13
... the square of the ratios of the corresponding sides.
5

12. (-1)^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...
x^(6-3) = x^3
5
1

13. Suppose that the graph of f(x) is the result of stretching y=x + 5 away from the x-axis by a factor of 2. What is the new equation for the graph f(x)?
An isosceles right triangle.
A 30-60-90 triangle.
y = (x + 5)/2
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

14. If Madagascar'S exports totaled 1.3 billion in 2009 - and 4% came from China - what was the value in millions of the country'S exports to China?
67 - 71 - 73
441000 = 1 10 10 10 21 * 21
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
52

15. What are the members or elements of a set?
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
The objects within a set.
5
Move the decimal point to the right x places

16. What is the 'Solution' for a system of linear equations?
Indeterminable.
The sum of digits is divisible by 9.
The point of intersection of the systems.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

17. Circumference of a circle?
0
6
4096
Diameter(Pi)

18. Can the output value of a function have more than one input value?
2.592 kg
Yes. [i.e. f(x) = x^2 - 1
The set of elements found in both A and B.
71 - 73 - 79

19. Simplify the expression [(b^2 - c^2) / (b - c)]
27^(-4)
(b + c)
11 - 13 - 17 - 19
The empty set - denoted by a circle with a diagonal through it.

20. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
28. n = 8 - k = 2. n! / k!(n-k)!
0
(n-2) x 180
4a^2(b)

21. What are the integers?
2.592 kg
(b + c)
All numbers multiples of 1.
Diameter(Pi)

22. Formula to find a circle'S circumference from its diameter?
The third side is greater than the difference and less than the sum.
C = (pi)d
75:11
Even

23. What is an exterior angle?
87.5%
Two angles whose sum is 90.
9 & 6/7
An angle which is supplementary to an interior angle.

24. What is a piecewise equation?
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
Two angles whose sum is 180.
12sqrt2
A chord is a line segment joining two points on a circle.

25. What is a parabola?
Ax^2 + bx + c where a -b and c are constants and a /=0
2.592 kg
The curve opens downward and the vertex is the maximum point on the graph.
The set of input values for a function.

26. Number of degrees in a triangle
Move the decimal point to the right x places
180
1
5

27. x^2 = 9. What is the value of x?
The second graph is less steep.
The set of elements which can be found in either A or B.
3 - -3
Two angles whose sum is 90.

28. What percent of 40 is 22?
1:sqrt3:2
IV
31 - 37
55%

29. Surface area for a cylinder?
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)
9 : 25
83.333%
2(pi)r^2 + 2(pi)rh

30. Which is greater? 64^5 or 16^8
The interesection of A and B.
...multiply by 100.
55%
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

31. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
...multiply by 100.
12! / 5!7! = 792
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
4.25 - 6 - 22

32. 30< all primes<40
2(pi)r^2 + 2(pi)rh
31 - 37
A chord is a line segment joining two points on a circle.
48

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.
90 degrees
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)
70
An infinite set.

34. a^0 =
x(x - y + 1)
y = (x + 5)/2
1
130pi

35. 7/8 in percent?
87.5%
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
72
An arc is a portion of a circumference of a circle.

36. What is the name for a grouping of the members within a set based on a shared characteristic?
Its last two digits are divisible by 4.
Sqrt 12
The longest arc between points A and B on a circle'S diameter.
A subset.

37. Hector invested $6000. Part was invested in account with 9% simple annual interest - and the rest in account with 7% simple annual interest. If he earned $490 in the first year of these investments - how much did he invest in each account?
413.03 / 10^4 (move the decimal point 4 places to the left)
$3 -500 in the 9% and $2 -500 in the 7%.
F(x-c)
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

38. 10<all primes<20
F(x) + c
1
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
11 - 13 - 17 - 19

39. A number is divisible by 9 if...
The overlapping sections.
62.5%
413.03 / 10^4 (move the decimal point 4 places to the left)
The sum of digits is divisible by 9.

40. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
A 30-60-90 triangle.
130pi
72
(a + b)^2

41. There are 10 finalists for the school spelling bee. A first - second - and third place trophy will be awarded. How many different people can get the three prizes?
The two xes after factoring.
Sqrt 12
10! / 3!(10-3)! = 120
F(x) + c

42. 60 < all primes <70
61 - 67
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
Relationship cannot be determined (what if x is negative?)
13pi / 2

43. 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?
3
A subset.
441000 = 1 10 10 10 21 * 21
The second graph is less steep.

44. a^2 - b^2 =
(a - b)(a + b)
Indeterminable.
41 - 43 - 47
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

45. What is an isoceles triangle?
Two equal sides and two equal angles.
Arc length = (n/360) x pi(2r) where n is the number of degrees.
x^(4+7) = x^11
8

46. Whats the difference between factors and multiples?
52
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
180
Factors are few - multiples are many.

47. 25^(1/2) or sqrt. 25 =
Infinite.
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.
An angle which is supplementary to an interior angle.
5 OR -5

48. What is the graph of f(x) shifted right c units or spaces?
A set with no members - denoted by a circle with a diagonal through it.
9 : 25
F(x-c)
5

49. 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
A grouping of the members within a set based on a shared characteristic.
The longest arc between points A and B on a circle'S diameter.
The steeper the slope.

50. A number is divisible by 6 if...
Its divisible by 2 and by 3.
Factors are few - multiples are many.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)