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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. Describe the relationship between 3x^2 and 3(x - 1)^2
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
1
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
Factors are few - multiples are many.

2. If an inequality is multiplied or divided by a negative number....
2sqrt6
An angle which is supplementary to an interior angle.
...multiply by 100.
The direction of the inequality is reversed.

3. What is the name of set with a number of elements which cannot be counted?
An infinite set.
F(x) + c
IV
No - only like radicals can be added.

4. 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?
The objects within a set.
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
N! / (k!)(n-k)!
2 & 3/7

5. Order of quadrants:
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
No - only like radicals can be added.
From northeast - counterclockwise. I - II - III - IV
A subset.

6. What are complementary angles?
Undefined - because we can'T divide by 0.
18
Two angles whose sum is 90.
83.333%

7. What is the measure of an exterior angle of a regular pentagon?
72
III
y = (x + 5)/2
87.5%

8. 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?
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
Yes - like radicals can be added/subtracted.
441000 = 1 10 10 10 21 * 21
... the square of the ratios of the corresponding sides.

9. How to determine percent decrease?
500
(amount of decrease/original price) x 100%
3
(a + b)^2

10. 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?
IV
500
The set of elements found in both A and B.
F(x + c)

11. P and r are factors of 100. What is greater - pr or 100?
A 30-60-90 triangle.
Indeterminable.
$3 -500 in the 9% and $2 -500 in the 7%.
180 degrees

12. What is the graph of f(x) shifted right c units or spaces?
The two xes after factoring.
Members or elements
F(x-c)
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)

13. a^2 - b^2
20.5
27^(-4)
Arc length = (n/360) x pi(2r) where n is the number of degrees.
(a - b)(a + b)

14. The objects in a set are called two names:
... the square of the ratios of the corresponding sides.
Members or elements
2(pi)r^2 + 2(pi)rh
A reflection about the axis.

15. 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?
4:5
N! / (n-k)!
A 30-60-90 triangle.
12! / 5!7! = 792

16. What are the rational numbers?
72
4096
12sqrt2
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

17. What is the side length of an equilateral triangle with altitude 6?
Divide by 100.
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...
1
Pi is the ratio of a circle'S circumference to its diameter.

18. What is the order of operations?
The set of output values for a function.
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
41 - 43 - 47
Ax^2 + bx + c where a -b and c are constants and a /=0

19. 60 < all primes <70
Yes. [i.e. f(x) = x^2 - 1
61 - 67
3/2 - 5/3
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

20. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
5 OR -5
Indeterminable.
(a - b)^2
A circle centered at -2 - -2 with radius 3.

21. 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?
1:sqrt3:2
48
The set of elements which can be found in either A or B.
Infinite.

22. 6w^2 - w - 15 = 0
12.5%
3/2 - 5/3
70
... the square of the ratios of the corresponding sides.

23. 2sqrt4 + sqrt4 =
55%
y = 2x^2 - 3
III
3sqrt4

24. a^2 + 2ab + b^2
(a + b)^2
87.5%
180 degrees
Yes. [i.e. f(x) = x^2 - 1

25. What is the 'Solution' for a system of linear equations?
A subset.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
The point of intersection of the systems.
Yes - like radicals can be added/subtracted.

26. Which quadrant is the lower left hand?
All numbers multiples of 1.
III
The steeper the slope.
83.333%

27. What is the name for a grouping of the members within a set based on a shared characteristic?
41 - 43 - 47
A subset.
Two angles whose sum is 90.
83.333%

28. The larger the absolute value of the slope...
The steeper the slope.
180 degrees
9 : 25
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)

29. Define a 'monomial'
A circle centered at -2 - -2 with radius 3.
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.
6
An expression with just one term (-6x - 2a^2)

30. (-1)^3 =
The longest arc between points A and B on a circle'S diameter.
F(x) + c
1
The union of A and B.

31. (6sqrt3) x (2sqrt5) =
Two angles whose sum is 180.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
Two equal sides and two equal angles.
6 : 1 : 2

32. What is the set of elements which can be found in either A or B?
The union of A and B.
From northeast - counterclockwise. I - II - III - IV
The overlapping sections.
Its divisible by 2 and by 3.

33. A number is divisible by 6 if...
4725
2sqrt6
(amount of increase/original price) x 100%
Its divisible by 2 and by 3.

34. 3/8 in percent?
37.5%
C = 2(pi)r
Lies opposite the greater angle
IV

35. 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
The set of input values for a function.
1:1:sqrt2
18
The point of intersection of the systems.

36. What number between 70 & 75 - inclusive - has the greatest number of factors?
72
Yes. [i.e. f(x) = x^2 - 1
Two angles whose sum is 90.
A central angle is an angle formed by 2 radii.

37. x^(-y)=
Its negative reciprocal. (-b/a)
True
Sector area = (n/360) X (pi)r^2
1/(x^y)

38. What is the 'union' of A and B?
2(pi)r^2 + 2(pi)rh
x^(6-3) = x^3
The set of elements which can be found in either A or B.
Undefined

39. What are the irrational numbers?

40. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
Infinite.
20.5
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.
2

41. x^2 = 9. What is the value of x?
The set of output values for a function.
1
3 - -3
Area of the base X height = (pi)hr^2

42. What is the absolute value function?
G(x) = {x}
From northeast - counterclockwise. I - II - III - IV
Cd
... the square of the ratios of the corresponding sides.

43. What is a parabola?
Arc length = (n/360) x pi(2r) where n is the number of degrees.
The sum of its digits is divisible by 3.
Ax^2 + bx + c where a -b and c are constants and a /=0
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

44. 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)!
13pi / 2
31 - 37
A = I (1 + rt)

45. What is the slope of a horizontal line?
180
6
(n-2) x 180
0

46. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
An isosceles right triangle.
2sqrt6
.0004809 X 10^11
0

47. What is the 'Range' of a series of numbers?
The greatest value minus the smallest.
9 : 25
A circle centered at -2 - -2 with radius 3.
F(x) - c

48. What is a set with no members called?
The empty set - denoted by a circle with a diagonal through it.
The set of elements found in both A and B.
F(x + c)
1/(x^y)

49. How to find the diagonal of a rectangular solid?
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
The union of A and B.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
Its divisible by 2 and by 3.

50. Reduce: 4.8 : 0.8 : 1.6
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
Triangles with same measure and same side lengths.
Undefined - because we can'T divide by 0.
6 : 1 : 2