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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. When the 'a' in a parabola is positive....
(b + c)
The interesection of A and B.
The curve opens upward and the vertex is the minimal point on the graph.
(base*height) / 2

2. (-1)^3 =
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
1
The curve opens downward and the vertex is the maximum point on the graph.
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)

3. Ratio of ages of Anna and Emma is 3:5 and of Emma and Nicolas is 3:5. What is the ratio of Anna to Nicholas' ages?
53 - 59
0
9 : 25
A = pi(r^2)

4. x^4 + x^7 =
II
x^(4+7) = x^11
7 / 1000
16.6666%

5. What is the order of operations?
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
A reflection about the axis.
72
The overlapping sections.

6. Can the input value of a function have more than one output value (i.e. x: y - y1)?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
No - the input value has exactly one output.
10
G(x) = {x}

7. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
From northeast - counterclockwise. I - II - III - IV
11 - 13 - 17 - 19
1
130pi

8. (a^-1)/a^5
A circle centered on the origin with radius 8.
48
1/a^6
Angle/360 x (pi)r^2

9. What is the set of elements which can be found in either A or B?
70
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
The union of A and B.
... the square of the ratios of the corresponding sides.

10. Define an 'expression'.
An arc is a portion of a circumference of a circle.
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)
G(x) = {x}
3 - -3

11. 40 < all primes<50
F(x + c)
x(x - y + 1)
180
41 - 43 - 47

12. 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)?
1
y = (x + 5)/2
$3 -500 in the 9% and $2 -500 in the 7%.
(a + b)^2

13. (12sqrt15) / (2sqrt5) =
5
28. n = 8 - k = 2. n! / k!(n-k)!
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
(a - b)^2

14. If you have a set of n objects - but you only want to order k of them - what formula do you use to determine the number of permutations?
N! / (n-k)!
72
All numbers multiples of 1.
(a + b)^2

15. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
288 (8 9 4)
(a - b)^2
12! / 5!7! = 792
Pi is the ratio of a circle'S circumference to its diameter.

16. What is the graph of f(x) shifted right c units or spaces?
Lies opposite the greater angle
True
F(x-c)
72

17. 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?
F(x + c)
3 - -3
6 : 1 : 2
10! / 3!(10-3)! = 120

18. 2sqrt4 + sqrt4 =
3sqrt4
1
2
The objects within a set.

19. What are the smallest three prime numbers greater than 65?
53 - 59
1
67 - 71 - 73
Two angles whose sum is 180.

20. What is the percent formula?
67 - 71 - 73
An arc is a portion of a circumference of a circle.
Part = Percent X Whole
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

21. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
A = I (1 + rt)
C = (pi)d
2sqrt6
The sum of its digits is divisible by 3.

22. What is the 'Range' of a series of numbers?
The greatest value minus the smallest.
A chord is a line segment joining two points on a circle.
III
75:11

23. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
.0004809 X 10^11
When the function is not defined for all real numbers -; only a subset of the real numbers.
4725
F(x-c)

24. What is the graph of f(x) shifted upward c units or spaces?
The interesection of A and B.
F(x) + c
(a - b)(a + b)
180

25. The ratio of the areas of two similar polygons is ...
... the square of the ratios of the corresponding sides.
Move the decimal point to the right x places
37.5%
10

26. Area of a triangle?
12sqrt2
6
55%
(base*height) / 2

27. a^2 + 2ab + b^2
(a + b)^2
2.592 kg
1
I

28. Max and Min lengths for a side of a triangle?
A circle centered at -2 - -2 with radius 3.
The empty set - denoted by a circle with a diagonal through it.
2(pi)r^2 + 2(pi)rh
The third side is greater than the difference and less than the sum.

29. When does a function automatically have a restricted domain (2)?
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
1.0843 X 10^11
1
... the square of the ratios of the corresponding sides.

30. a^2 - b^2
(n-2) x 180
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
(a - b)(a + b)
A circle centered on the origin with radius 8.

31. What is a parabola?
2.592 kg
Ax^2 + bx + c where a -b and c are constants and a /=0
4a^2(b)
The overlapping sections.

32. Solve the quadratic equation ax^2 + bx + c= 0
Undefined - because we can'T divide by 0.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
52
1/2 times 7/3

33. Surface area for a cylinder?
1
From northeast - counterclockwise. I - II - III - IV
2(pi)r^2 + 2(pi)rh
The second graph is less steep.

34. A number is divisible by 3 if ...
The sum of its digits is divisible by 3.
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
4:5
13pi / 2

35. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
A circle centered at -2 - -2 with radius 3.
N! / (k!)(n-k)!
Even
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]

36. What is the surface area of a cylinder with radius 5 and height 8?
130pi
(n-2) x 180
2(pi)r^2 + 2(pi)rh
The steeper the slope.

37. A cylinder has a surface area of 22pi. If the cylinder has a height of 10 - what is the radius?
413.03 / 10^4 (move the decimal point 4 places to the left)
1
6
Its divisible by 2 and by 3.

38. x^(-y)=
Even
4725
1/(x^y)
The curve opens upward and the vertex is the minimal point on the graph.

39. 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)
Yes - like radicals can be added/subtracted.
Arc length = (n/360) x pi(2r) where n is the number of degrees.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.

40. a^2 - b^2 =
(a - b)(a + b)
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.
No - only like radicals can be added.

41. Formula of rectangle where l increases by 20% and w decreases by 20%
x= (1.2)(.8)lw
A set with no members - denoted by a circle with a diagonal through it.
An arc is a portion of a circumference of a circle.
A circle centered at -2 - -2 with radius 3.

42. A number is divisible by 4 is...
Its last two digits are divisible by 4.
(a - b)(a + b)
1 & 37/132
The objects within a set.

43. Which is greater? 27^(-4) or 9^(-8)
0
Divide by 100.
27^(-4)
Undefined

44. How to determine percent increase?
Area of the base X height = (pi)hr^2
(amount of increase/original price) x 100%
16.6666%
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

45. How to find the area of a sector?
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
Angle/360 x (pi)r^2
F(x) - c
$11 -448

46. What is the formula for computing simple interest?
A = I (1 + rt)
1
No - the input value has exactly one output.
A reflection about the origin.

47. Which quadrant is the lower left hand?
III
A grouping of the members within a set based on a shared characteristic.
Factors are few - multiples are many.
An isosceles right triangle.

48. (6sqrt3) x (2sqrt5) =
The longest arc between points A and B on a circle'S diameter.
Cd
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
75:11

49. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
4725
A subset.
28. n = 8 - k = 2. n! / k!(n-k)!
Angle/360 x (pi)r^2

50. 1/8 in percent?
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
16.6666%
12.5%
A circle centered at -2 - -2 with radius 3.