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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. Legs 6 - 8. Hypotenuse?
x(x - y + 1)
10
True
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

2. What is the name for a grouping of the members within a set based on a shared characteristic?
...multiply by 100.
75:11
A subset.
4a^2(b)

3. Which is greater? 27^(-4) or 9^(-8)
48
(a - b)(a + b)
The sum of digits is divisible by 9.
27^(-4)

4. What is the absolute value function?
4a^2(b)
G(x) = {x}
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
An expression with just one term (-6x - 2a^2)

5. Formula to calculate arc length?
180 degrees
F(x) + c
1
Arc length = (n/360) x pi(2r) where n is the number of degrees.

6. 10<all primes<20
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)
x^(6-3) = x^3
The shortest arc between points A and B on a circle'S diameter.
11 - 13 - 17 - 19

7. How to determine percent increase?
16.6666%
(amount of increase/original price) x 100%
10! / (10-3)! = 720
18

8. How to determine percent decrease?
130pi
(amount of increase/original price) x 100%
(amount of decrease/original price) x 100%
The curve opens upward and the vertex is the minimal point on the graph.

9. 2sqrt4 + sqrt4 =
4:5
1
3 - -3
3sqrt4

10. Solve the quadratic equation ax^2 + bx + c= 0
x= (1.2)(.8)lw
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
All numbers multiples of 1.
The two xes after factoring.

11. Reduce: 4.8 : 0.8 : 1.6
6 : 1 : 2
III
A = pi(r^2)
y = (x + 5)/2

12. Define a 'monomial'
An expression with just one term (-6x - 2a^2)
90
The objects within a set.
23 - 29

13. Factor a^2 + 2ab + b^2
130pi
6
(a + b)^2
The point of intersection of the systems.

14. The perimeter of a square is 48 inches. The length of its diagonal is:
Part = Percent X Whole
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
12sqrt2
The sum of digits is divisible by 9.

15. Area of a triangle?
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
(amount of decrease/original price) x 100%
(base*height) / 2
Divide by 100.

16. What is the maximum value for the function g(x) = (-2x^2) -1?
1
(a - b)(a + b)
(a + b)^2
Two equal sides and two equal angles.

17. 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
Triangles with same measure and same side lengths.
18
The third side is greater than the difference and less than the sum.

18. 1/2 divided by 3/7 is the same as
16.6666%
53 - 59
1/2 times 7/3
3/2 - 5/3

19. How many multiples does a given number have?
The shortest arc between points A and B on a circle'S diameter.
13pi / 2
Infinite.
An infinite set.

20. (-1)^2 =
...multiply by 100.
1
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
3

21. What is the 'union' of A and B?
The set of elements which can be found in either A or B.
23 - 29
An angle which is supplementary to an interior angle.
1.7

22. How many 3-digit positive integers are even and do not contain the digit 4?
288 (8 9 4)
The sum of digits is divisible by 9.
x^(6-3) = x^3
G(x) = {x}

23. What is the graph of f(x) shifted downward c units or spaces?
1
C = (pi)d
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)
F(x) - c

24. What is the sum of the angles of a triangle?
180 degrees
Angle/360 x (pi)r^2
III
37.5%

25. What is the ratio of the sides of an isosceles right triangle?
1:1:sqrt2
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
10
62.5%

26. 7/8 in percent?
A set with a number of elements which can be counted.
83.333%
6
87.5%

27. Max and Min lengths for a side of a triangle?
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)
An expression with just one term (-6x - 2a^2)
72
The third side is greater than the difference and less than the sum.

28. If Madagascar'S exports totaled 1.3 billion in 2009 - and 4% came from China - what was the value in millions of the country'S exports to China?
52
Undefined
12.5%
23 - 29

29. 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?
28. n = 8 - k = 2. n! / k!(n-k)!
Indeterminable.
Its divisible by 2 and by 3.
500

30. What is the empty set?
12! / 5!7! = 792
An arc is a portion of a circumference of a circle.
G(x) = {x}
A set with no members - denoted by a circle with a diagonal through it.

31. 25^(1/2) or sqrt. 25 =
x(x - y + 1)
5 OR -5
The sum of its digits is divisible by 3.
$11 -448

32. What is the surface area of a cylinder with radius 5 and height 8?
130pi
1
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
Part = Percent X Whole

33. Simplify the expression (p^2 - q^2)/ -5(q - p)
70
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)
1
(p + q)/5

34. What are the real numbers?
9 & 6/7
G(x) = {x}
8
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)

35. 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?
A grouping of the members within a set based on a shared characteristic.
9 & 6/7
75:11
7 / 1000

36. Legs: 3 - 4. Hypotenuse?
1
5
18
No - only like radicals can be added.

37. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
y = (x + 5)/2
A circle centered at -2 - -2 with radius 3.
Ax^2 + bx + c where a -b and c are constants and a /=0
4a^2(b)

38. How many sides does a hexagon have?
6
Pi is the ratio of a circle'S circumference to its diameter.
Members or elements
The longest arc between points A and B on a circle'S diameter.

39. x^(-y)=
3sqrt4
1/(x^y)
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
(b + c)

40. a^2 - b^2 =
(a - b)(a + b)
3
F(x + c)
Pi is the ratio of a circle'S circumference to its diameter.

41. Can you subtract 3sqrt4 from sqrt4?
Yes - like radicals can be added/subtracted.
The set of input values for a function.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
90 degrees

42. 50 < all primes< 60
53 - 59
288 (8 9 4)
An angle which is supplementary to an interior angle.
5

43. Which quadrant is the upper left hand?
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
83.333%
A central angle is an angle formed by 2 radii.
II

44. What number between 70 & 75 - inclusive - has the greatest number of factors?
Arc length = (n/360) x pi(2r) where n is the number of degrees.
72
Diameter(Pi)
10

45. What is an isoceles triangle?
Two equal sides and two equal angles.
Its divisible by 2 and by 3.
I
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

46. 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
3 - -3
... the square of the ratios of the corresponding sides.
x^(4+7) = x^11

47. Formula to find a circle'S circumference from its diameter?
When the function is not defined for all real numbers -; only a subset of the real numbers.
31 - 37
Angle/360 x 2(pi)r
C = (pi)d

48. 70 < all primes< 80
71 - 73 - 79
Part = Percent X Whole
20.5
Two equal sides and two equal angles.

49. What is the area of a regular hexagon with side 6?
62.5%
Lies opposite the greater angle
1
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

50. What is a central angle?
28. n = 8 - k = 2. n! / k!(n-k)!
1.7
A central angle is an angle formed by 2 radii.
The curve opens upward and the vertex is the minimal point on the graph.