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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. What is the ratio of the surface area of a cube with an edge of 10 to the surface area of a rectangular solid with dimensions 2 - 4 - and 6?
500
75:11
1 & 37/132
No - the input value has exactly one output.

2. 0^0
67 - 71 - 73
Undefined
13
72

3. (x^2)^4
The objects within a set.
x^(2(4)) =x^8 = (x^4)^2
31 - 37
An expression with just one term (-6x - 2a^2)

4. a^2 - b^2
F(x) - c
(a + b)^2
The sum of its digits is divisible by 3.
(a - b)(a + b)

5. 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 elements which can be found in either A or B.
6
500
Indeterminable.

6. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
The set of elements which can be found in either A or B.
2sqrt6
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
.0004809 X 10^11

7. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
2^9 / 2 = 256
20.5
0
1

8. x^2 = 9. What is the value of x?
Angle/360 x (pi)r^2
3 - -3
Sector area = (n/360) X (pi)r^2
37.5%

9. What is a subset?
7 / 1000
All numbers multiples of 1.
A grouping of the members within a set based on a shared characteristic.
9 : 25

10. A number is divisible by 3 if ...
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
The sum of its digits is divisible by 3.
The two xes after factoring.
(amount of increase/original price) x 100%

11. Can you subtract 3sqrt4 from sqrt4?
Yes - like radicals can be added/subtracted.
Pi is the ratio of a circle'S circumference to its diameter.
180 degrees
(n-2) x 180

12. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
6 : 1 : 2
x^(4+7) = x^11
Its divisible by 2 and by 3.
1

13. What is the set of elements which can be found in either A or B?
The union of A and B.
The interesection of A and B.
1/2 times 7/3
N! / (n-k)!

14. Legs: 3 - 4. Hypotenuse?
1:sqrt3:2
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)
5
Move the decimal point to the right x places

15. What is a finite set?
A set with a number of elements which can be counted.
90
1.0843 X 10^11
Part = Percent X Whole

16. Whats the difference between factors and multiples?
$3 -500 in the 9% and $2 -500 in the 7%.
Factors are few - multiples are many.
12.5%
A central angle is an angle formed by 2 radii.

17. Which quadrant is the upper left hand?
IV
The interesection of A and B.
Cd
II

18. Area of a triangle?
3
Ax^2 + bx + c where a -b and c are constants and a /=0
5
(base*height) / 2

19. What is the surface area of a cylinder with radius 5 and height 8?
The sum of its digits is divisible by 3.
130pi
From northeast - counterclockwise. I - II - III - IV
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

20. (-1)^3 =
37.5%
Its divisible by 2 and by 3.
1
2(pi)r^2 + 2(pi)rh

21. What is a tangent?
A tangent is a line that only touches one point on the circumference of a circle.
13
61 - 67
11 - 13 - 17 - 19

22. If an inequality is multiplied or divided by a negative number....
0
The direction of the inequality is reversed.
A reflection about the origin.
C = (pi)d

23. 70 < all primes< 80
10
71 - 73 - 79
(amount of decrease/original price) x 100%
12sqrt2

24. 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
Area of the base X height = (pi)hr^2
1.0843 X 10^11
Sqrt 12

25. Which quadrant is the lower left hand?
An angle which is supplementary to an interior angle.
III
Triangles with same measure and same side lengths.
1

26. What are congruent triangles?
2
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
Triangles with same measure and same side lengths.
Even

27. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
A set with a number of elements which can be counted.
13pi / 2
(a - b)^2
F(x) - c

28. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
$11 -448
16.6666%
1
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

29. How many sides does a hexagon have?
6
1 & 37/132
F(x-c)
Divide by 100.

30. What is the slope of a horizontal line?
... the square of the ratios of the corresponding sides.
0
The curve opens upward and the vertex is the minimal point on the graph.
y = 2x^2 - 3

31. a^2 + 2ab + b^2
1.7
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
(a + b)^2
75:11

32. What is the ratio of the sides of an isosceles right triangle?
An expression with just one term (-6x - 2a^2)
Factors are few - multiples are many.
1:1:sqrt2
A central angle is an angle formed by 2 radii.

33. Number of degrees in a triangle
The overlapping sections.
A 30-60-90 triangle.
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...
180

34. What is the measure of an exterior angle of a regular pentagon?
72
The curve opens upward and the vertex is the minimal point on the graph.
Sector area = (n/360) X (pi)r^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.

35. What is the 'union' of A and B?
(base*height) / 2
$3 -500 in the 9% and $2 -500 in the 7%.
The set of elements which can be found in either A or B.
4a^2(b)

36. Which is greater? 200x^295 or 10x^294?
Ax^2 + bx + c where a -b and c are constants and a /=0
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
The two xes after factoring.
Relationship cannot be determined (what if x is negative?)

37. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
The third side is greater than the difference and less than the sum.
1
y = 2x^2 - 3
8

38. x^6 / x^3
53 - 59
x^(6-3) = x^3
A reflection about the origin.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

39. 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?
500
10! / 3!(10-3)! = 120
11 - 13 - 17 - 19
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...

40. What is the graph of f(x) shifted upward c units or spaces?
The sum of its digits is divisible by 3.
F(x) + c
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
6

41. Describe the relationship between 3x^2 and 3(x - 1)^2
Diameter(Pi)
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
75:11
90

42. 30< all primes<40
13pi / 2
31 - 37
Sector area = (n/360) X (pi)r^2
90

43. What is the slope of a vertical line?

44. 5x^2 - 35x -55 = 0
(base*height) / 2
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
Undefined - because we can'T divide by 0.
.0004809 X 10^11

45. What are the real numbers?
3sqrt4
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)
A 30-60-90 triangle.
441000 = 1 10 10 10 21 * 21

46. What is the empty set?
Relationship cannot be determined (what if x is negative?)
A set with no members - denoted by a circle with a diagonal through it.
G(x) = {x}
An arc is a portion of a circumference of a circle.

47. What is the sum of the angles of a triangle?
75:11
180 degrees
16.6666%
Yes - like radicals can be added/subtracted.

48. What are the irrational numbers?

49. Can you add sqrt 3 and sqrt 5?
7 / 1000
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
No - only like radicals can be added.
Factors are few - multiples are many.

50. 1/2 divided by 3/7 is the same as
The steeper the slope.
27^(-4)
1/2 times 7/3
An angle which is supplementary to an interior angle.