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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. 1/8 in percent?
The set of output values for a function.
12.5%
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
71 - 73 - 79

2. x^4 + x^7 =
8
10! / 3!(10-3)! = 120
23 - 29
x^(4+7) = x^11

3. 5x^2 - 35x -55 = 0
C = (pi)d
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.
1
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]

4. 25^(1/2) or sqrt. 25 =
Two angles whose sum is 180.
5 OR -5
y = 2x^2 - 3
A tangent is a line that only touches one point on the circumference of a circle.

5. Factor a^2 + 2ab + b^2
16.6666%
(a + b)^2
9 & 6/7
6 : 1 : 2

6. Can you add sqrt 3 and sqrt 5?
The interesection of A and B.
No - only like radicals can be added.
The direction of the inequality is reversed.
Area of the base X height = (pi)hr^2

7. What is a parabola?
A subset.
72
Ax^2 + bx + c where a -b and c are constants and a /=0
A chord is a line segment joining two points on a circle.

8. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
1:sqrt3:2
8
4:5
Undefined - because we can'T divide by 0.

9. 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?
$3 -500 in the 9% and $2 -500 in the 7%.
90
A 30-60-90 triangle.
A set with no members - denoted by a circle with a diagonal through it.

10. Can you simplify sqrt72?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
67 - 71 - 73
G(x) = {x}
Its last two digits are divisible by 4.

11. There are 10 finalists for the school spelling bee. A first - second - and third place trophy will be awarded. In how many ways can the judges award the 3 prizes?
10! / (10-3)! = 720
1
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
11 - 13 - 17 - 19

12. Which is greater? 200x^295 or 10x^294?
Relationship cannot be determined (what if x is negative?)
Area of the base X height = (pi)hr^2
(a - b)(a + b)
1

13. What is the 'Restricted domain of a function'?
N! / (n-k)!
500
(amount of decrease/original price) x 100%
When the function is not defined for all real numbers -; only a subset of the real numbers.

14. Formula to calculate arc length?
A grouping of the members within a set based on a shared characteristic.
6 : 1 : 2
Arc length = (n/360) x pi(2r) where n is the number of degrees.
(a - b)^2

15. Circumference of a circle?
Diameter(Pi)
Triangles with same measure and same side lengths.
180
(amount of increase/original price) x 100%

16. The ratio of the areas of two similar polygons is ...
... the square of the ratios of the corresponding sides.
7 / 1000
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
From northeast - counterclockwise. I - II - III - IV

17. 413.03 x 10^(-4) =
The shortest arc between points A and B on a circle'S diameter.
413.03 / 10^4 (move the decimal point 4 places to the left)
48
C = (pi)d

18. How to determine percent decrease?
12! / 5!7! = 792
The third side is greater than the difference and less than the sum.
Angle/360 x (pi)r^2
(amount of decrease/original price) x 100%

19. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
y = (x + 5)/2
... the square of the ratios of the corresponding sides.
4a^2(b)
A reflection about the origin.

20. Evaluate (4^3)^2
1
4096
The third side is greater than the difference and less than the sum.
1.0843 X 10^11

21. Solve the quadratic equation ax^2 + bx + c= 0
Two angles whose sum is 90.
Move the decimal point to the right x places
(base*height) / 2
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

22. A cylinder has a surface area of 22pi. If the cylinder has a height of 10 - what is the radius?
x^(2(4)) =x^8 = (x^4)^2
1
90pi
The direction of the inequality is reversed.

23. What is the measure of an exterior angle of a regular pentagon?
72
1/a^6
2^9 / 2 = 256
2 & 3/7

24. To convert a decimal to a percent...
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The sum of digits is divisible by 9.
3
...multiply by 100.

25. What does scientific notation mean?
55%
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
Even
5 OR -5

26. Which quandrant is the lower right hand?
The empty set - denoted by a circle with a diagonal through it.
10
41 - 43 - 47
IV

27. Formula for the area of a sector of a circle?
2 & 3/7
1/2 times 7/3
Sector area = (n/360) X (pi)r^2
Divide by 100.

28. What is the order of operations?
70
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

29. 0^0
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...
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
12! / 5!7! = 792
Undefined

30. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
90
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...
A grouping of the members within a set based on a shared characteristic.
(p + q)/5

31. Length of an arc of a circle?
Area of the base X height = (pi)hr^2
True
When the function is not defined for all real numbers -; only a subset of the real numbers.
Angle/360 x 2(pi)r

32. What are congruent triangles?
True
61 - 67
Triangles with same measure and same side lengths.
5

33. What is the set of elements found in both A and B?
A circle centered at -2 - -2 with radius 3.
The interesection of A and B.
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)
87.5%

34. What are the integers?
An isosceles right triangle.
Factors are few - multiples are many.
The set of input values for a function.
All numbers multiples of 1.

35. How to find the area of a sector?
3 - -3
6
62.5%
Angle/360 x (pi)r^2

36. Describe the relationship between 3x^2 and 3(x - 1)^2
11 - 13 - 17 - 19
The longest arc between points A and B on a circle'S diameter.
...multiply by 100.
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

37. Which is greater? 27^(-4) or 9^(-8)
A central angle is an angle formed by 2 radii.
71 - 73 - 79
4725
27^(-4)

38. What are the smallest three prime numbers greater than 65?
Even
67 - 71 - 73
4.25 - 6 - 22
Indeterminable.

39. What is the empty set?
1/2 times 7/3
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)
6
A set with no members - denoted by a circle with a diagonal through it.

40. The objects in a set are called two names:
4.25 - 6 - 22
Members or elements
90 degrees
Undefined

41. What number between 70 & 75 - inclusive - has the greatest number of factors?
12! / 5!7! = 792
Angle/360 x (pi)r^2
72
7 / 1000

42. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
1
6
Move the decimal point to the right x places
70

43. 3/8 in percent?
53 - 59
Divide by 100.
37.5%
An arc is a portion of a circumference of a circle.

44. What transformation occurs if point C is reflected over the x-axis and then the y-axis?
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)
1:1:sqrt2
A reflection about the axis.
(base*height) / 2

45. Find the surface area of a cylinder with radius 3 and height 12.
(a - b)(a + b)
67 - 71 - 73
90pi
1

46. What is the 'domain' of a function?
2(pi)r^2 + 2(pi)rh
The set of input values for a function.
A = I (1 + rt)
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)

47. What are the rational numbers?
1:sqrt3:2
3 - -3
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
F(x) - c

48. What is the 'Solution' for a set of inequalities.
4:5
The objects within a set.
2.592 kg
The overlapping sections.

49. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
Factors are few - multiples are many.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
The steeper the slope.
4096

50. Volume for a cylinder?
Area of the base X height = (pi)hr^2
A grouping of the members within a set based on a shared characteristic.
52
Lies opposite the greater angle