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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. Surface area for a cylinder?
The interesection of A and B.
2(pi)r^2 + 2(pi)rh
(a + b)^2
Undefined

2. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
The curve opens downward and the vertex is the maximum point on the graph.
3sqrt4
4:5
1

3. What does scientific notation mean?
C = 2(pi)r
6
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

4. (6sqrt3) x (2sqrt5) =
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
The empty set - denoted by a circle with a diagonal through it.
x^(4+7) = x^11

5. Formula to find a circle'S circumference from its radius?
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
A = I (1 + rt)
C = 2(pi)r
71 - 73 - 79

6. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
4:5
75:11
C = (pi)d
1

7. Legs 6 - 8. Hypotenuse?
The direction of the inequality is reversed.
II
10
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

8. In a regular polygon with n sides - the formula for the sum of interior angles
Lies opposite the greater angle
(b + c)
The curve opens downward and the vertex is the maximum point on the graph.
(n-2) x 180

9. 5 bakeries sell an average of 300 muffins per bakery per day. If 2 stop making muffins but the total muffins sold stays the same - what is the average of muffins per bakery sold among the remaining?
No - only like radicals can be added.
23 - 29
500
The third side is greater than the difference and less than the sum.

10. Area of a triangle?
A 30-60-90 triangle.
(base*height) / 2
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
A central angle is an angle formed by 2 radii.

11. Formula for the area of a circle?
2^9 / 2 = 256
An isosceles right triangle.
A = pi(r^2)
$3 -500 in the 9% and $2 -500 in the 7%.

12. 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?
441000 = 1 10 10 10 21 * 21
67 - 71 - 73
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)
(a - b)(a + b)

13. Volume for a cylinder?
Area of the base X height = (pi)hr^2
20.5
x^(4+7) = x^11
2^9 / 2 = 256

14. What is the area of a regular hexagon with side 6?
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
1:1:sqrt2
10
3sqrt4

15. What is the sum of the angles of a triangle?
3
180 degrees
The set of elements found in both A and B.
The point of intersection of the systems.

16. What is the graph of f(x) shifted upward c units or spaces?
F(x) + c
The direction of the inequality is reversed.
True
5 OR -5

17. Can the output value of a function have more than one input value?
A = I (1 + rt)
53 - 59
Yes. [i.e. f(x) = x^2 - 1
(a + b)^2

18. T or F? Given d -e &f =/ 0 - [(d^3)e(f^5)] / 2d(e^3) / [3(d^2)(e^3)(f^7)] / [6(e^5)(f^2)]?
Its negative reciprocal. (-b/a)
6
Sqrt 12
True

19. 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?
1/(x^y)
$3 -500 in the 9% and $2 -500 in the 7%.
Triangles with same measure and same side lengths.
.0004809 X 10^11

20. 7/8 in percent?
Its divisible by 2 and by 3.
N! / (k!)(n-k)!
87.5%
I

21. What is the ratio of the sides of an isosceles right triangle?
37.5%
1:1:sqrt2
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
Diameter(Pi)

22. Which is greater? 27^(-4) or 9^(-8)
27^(-4)
28. n = 8 - k = 2. n! / k!(n-k)!
All numbers multiples of 1.
16.6666%

23. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
2sqrt6
The sum of its digits is divisible by 3.
A set with a number of elements which can be counted.

24. Which quadrant is the upper right hand?
16.6666%
I
Sector area = (n/360) X (pi)r^2
A = I (1 + rt)

25. What is the 'Range' of a series of numbers?
The set of elements found in both A and B.
90
The greatest value minus the smallest.
When the function is not defined for all real numbers -; only a subset of the real numbers.

26. 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?
x= (1.2)(.8)lw
y = 2x^2 - 3
Members or elements
A = pi(r^2)

27. Legs: 3 - 4. Hypotenuse?
The set of input values for a function.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
5
Its divisible by 2 and by 3.

28. 413.03 x 10^(-4) =
The second graph is less steep.
2.592 kg
413.03 / 10^4 (move the decimal point 4 places to the left)
8

29. What is a minor arc?

30. a^2 + 2ab + b^2
The sum of digits is divisible by 9.
12sqrt2
C = (pi)d
(a + b)^2

31. How many 3-digit positive integers are even and do not contain the digit 4?
288 (8 9 4)
The set of elements found in both A and B.
61 - 67
... the square of the ratios of the corresponding sides.

32. How to find the circumference of a circle which circumscribes a square?
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
70
The objects within a set.
The set of elements which can be found in either A or B.

33. Factor x^2 - xy + x.
A reflection about the origin.
(a + b)^2
41 - 43 - 47
x(x - y + 1)

34. What are the rational numbers?
Pi is the ratio of a circle'S circumference to its diameter.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
F(x) - c
x= (1.2)(.8)lw

35. 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)!
Infinite.
75:11
A central angle is an angle formed by 2 radii.

36. 1/6 in percent?
16.6666%
9 & 6/7
The direction of the inequality is reversed.
Angle/360 x 2(pi)r

37. What are the roots of the quadrinomial x^2 + 2x + 1?
180 degrees
2.592 kg
The two xes after factoring.
... the square of the ratios of the corresponding sides.

38. Pi is a ratio of what to what?

39. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
70
An isosceles right triangle.
27^(-4)
2sqrt6

40. What is the graph of f(x) shifted downward c units or spaces?
55%
12! / 5!7! = 792
90 degrees
F(x) - c

41. What is the absolute value function?
G(x) = {x}
The greatest value minus the smallest.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
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...

42. The objects in a set are called two names:
Members or elements
When the function is not defined for all real numbers -; only a subset of the real numbers.
53 - 59
(base*height) / 2

43. 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.
A reflection about the axis.
Divide by 100.
90 degrees
A tangent is a line that only touches one point on the circumference of a circle.

44. To convert a percent to a fraction....
Divide by 100.
Two angles whose sum is 180.
x(x - y + 1)
No - the input value has exactly one output.

45. Find the surface area of a cylinder with radius 3 and height 12.
2^9 / 2 = 256
90pi
5
The third side is greater than the difference and less than the sum.

46. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
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)
Ax^2 + bx + c where a -b and c are constants and a /=0
A circle centered at -2 - -2 with radius 3.
23 - 29

47. What are congruent triangles?
441000 = 1 10 10 10 21 * 21
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
Its divisible by 2 and by 3.
Triangles with same measure and same side lengths.

48. x^4 + x^7 =
x^(4+7) = x^11
1/(x^y)
Ax^2 + bx + c where a -b and c are constants and a /=0
A tangent is a line that only touches one point on the circumference of a circle.

49. How to determine percent decrease?
Two equal sides and two equal angles.
(amount of decrease/original price) x 100%
4.25 - 6 - 22
28. n = 8 - k = 2. n! / k!(n-k)!

50. (-1)^2 =
N! / (k!)(n-k)!
2 & 3/7
1
(a + b)^2