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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. 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.
72
90 degrees
1
2^9 / 2 = 256

2. What are the real numbers?
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)
Cd
10! / 3!(10-3)! = 120
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)

3. Area of a triangle?
(base*height) / 2
The empty set - denoted by a circle with a diagonal through it.
Even
3

4. What does scientific notation mean?
Diameter(Pi)
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
180
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

5. 3/8 in percent?
The sum of its digits is divisible by 3.
G(x) = {x}
500
37.5%

6. Which quadrant is the upper left hand?
67 - 71 - 73
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
9 & 6/7
II

7. a^0 =
The curve opens upward and the vertex is the minimal point on the graph.
1
130pi
Its last two digits are divisible by 4.

8. Can you add sqrt 3 and sqrt 5?
No - only like radicals can be added.
10! / 3!(10-3)! = 120
The steeper the slope.
Arc length = (n/360) x pi(2r) where n is the number of degrees.

9. x^6 / x^3
Pi is the ratio of a circle'S circumference to its diameter.
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
1.7
x^(6-3) = x^3

10. How to determine percent increase?
(amount of increase/original price) x 100%
0
F(x-c)
$3 -500 in the 9% and $2 -500 in the 7%.

11. What number between 70 & 75 - inclusive - has the greatest number of factors?
72
F(x-c)
12! / 5!7! = 792
The overlapping sections.

12. What is the graph of f(x) shifted right c units or spaces?
F(x-c)
3
1/(x^y)
The steeper the slope.

13. 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?
The set of input values for a function.
500
A circle centered at -2 - -2 with radius 3.
An infinite set.

14. Simplify (a^2 + b)^2 - (a^2 - b)^2
10! / 3!(10-3)! = 120
Factors are few - multiples are many.
.0004809 X 10^11
4a^2(b)

15. 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?
The greatest value minus the smallest.
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
No - only like radicals can be added.
441000 = 1 10 10 10 21 * 21

16. 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?
Diameter(Pi)
y = 2x^2 - 3
12! / 5!7! = 792
1

17. How to find the area of a sector?
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
y = 2x^2 - 3
Angle/360 x (pi)r^2
True

18. 5x^2 - 35x -55 = 0
F(x + c)
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
10! / (10-3)! = 720
3 - -3

19. If an inequality is multiplied or divided by a negative number....
The direction of the inequality is reversed.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
F(x + c)
Sector area = (n/360) X (pi)r^2

20. When does a function automatically have a restricted domain (2)?
(a - b)^2
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
10! / 3!(10-3)! = 120
441000 = 1 10 10 10 21 * 21

21. Whats the difference between factors and multiples?
The objects within a set.
12.5%
Factors are few - multiples are many.
67 - 71 - 73

22. 60 < all primes <70
61 - 67
52
20.5
2^9 / 2 = 256

23. The ratio of the areas of two similar polygons is ...
The third side is greater than the difference and less than the sum.
... the square of the ratios of the corresponding sides.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
Two angles whose sum is 90.

24. What is the set of elements which can be found in either A or B?
A subset.
The union of A and B.
IV
I

25. If the two sides of a triangle are unequal then the longer side...
Part = Percent X Whole
2(pi)r^2 + 2(pi)rh
Two equal sides and two equal angles.
Lies opposite the greater angle

26. Write 10 -843 X 10^7 in scientific notation
1
A set with no members - denoted by a circle with a diagonal through it.
1.0843 X 10^11
A circle centered at -2 - -2 with radius 3.

27. What is the surface area of a cylinder with radius 5 and height 8?
4.25 - 6 - 22
Its divisible by 2 and by 3.
Diameter(Pi)
130pi

28. Factor a^2 + 2ab + b^2
F(x) - c
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)^2
Relationship cannot be determined (what if x is negative?)

29. 413.03 x 10^(-4) =
The third side is greater than the difference and less than the sum.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
413.03 / 10^4 (move the decimal point 4 places to the left)
2.592 kg

30. a^2 - 2ab + b^2
Two angles whose sum is 180.
An angle which is supplementary to an interior angle.
(a - b)^2
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.

31. A brick with dimensions 10. 15 and 25 weighs 1.5 kg. A second brick (same density) has dimensions 12 - 18 - and 30. What is the weight of the second brick?
2.592 kg
67 - 71 - 73
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...
II

32. Length of an arc of a circle?
The direction of the inequality is reversed.
Angle/360 x 2(pi)r
A tangent is a line that only touches one point on the circumference of a circle.
(n-2) x 180

33. Number of degrees in a triangle
Diameter(Pi)
180
2sqrt6
71 - 73 - 79

34. Formula for the area of a sector of a circle?
10! / (10-3)! = 720
53 - 59
Sector area = (n/360) X (pi)r^2
9 : 25

35. Which quadrant is the upper right hand?
10! / 3!(10-3)! = 120
I
Move the decimal point to the right x places
Pi is the ratio of a circle'S circumference to its diameter.

36. What are the rational numbers?
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)
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
Arc length = (n/360) x pi(2r) where n is the number of degrees.
1

37. What is the ratio of the sides of a 30-60-90 triangle?
13
Relationship cannot be determined (what if x is negative?)
1:sqrt3:2
3sqrt4

38. (6sqrt3) x (2sqrt5) =
A = I (1 + rt)
The steeper the slope.
The direction of the inequality is reversed.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

39. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
12! / 5!7! = 792
(a - b)(a + b)
90 degrees
C = (pi)d

40. Define an 'expression'.
90 degrees
No - the input value has exactly one output.
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)
Relationship cannot be determined (what if x is negative?)

41. What is the 'Solution' for a system of linear equations?
5
48
Two angles whose sum is 90.
The point of intersection of the systems.

42. 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?
48
0
71 - 73 - 79
I

43. What is the 'domain' of a function?
52
The set of input values for a function.
$3 -500 in the 9% and $2 -500 in the 7%.
2sqrt6

44. Formula for the area of a circle?
x^(4+7) = x^11
y = (x + 5)/2
Pi is the ratio of a circle'S circumference to its diameter.
A = pi(r^2)

45. 2sqrt4 + sqrt4 =
5
All numbers multiples of 1.
3sqrt4
Indeterminable.

46. What does the graph x^2 + y^2 = 64 look like?
The greatest value minus the smallest.
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.
A circle centered on the origin with radius 8.
5

47. 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
18
Its divisible by 2 and by 3.
x^(6-3) = x^3
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

48. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
Two equal sides and two equal angles.
4096
28. n = 8 - k = 2. n! / k!(n-k)!
1

49. How to determine percent decrease?
(amount of decrease/original price) x 100%
N! / (n-k)!
Undefined
IV

50. (x^2)^4
61 - 67
x^(2(4)) =x^8 = (x^4)^2
0
23 - 29