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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 percent formula?
37.5%
Its last two digits are divisible by 4.
Part = Percent X Whole
10! / 3!(10-3)! = 120

2. What is the 'domain' of a function?
Triangles with same measure and same side lengths.
The set of input values for a function.
55%
...multiply by 100.

3. Can you subtract 3sqrt4 from sqrt4?
70
Pi is the ratio of a circle'S circumference to its diameter.
Yes - like radicals can be added/subtracted.
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.

4. 40 < all primes<50
Area of the base X height = (pi)hr^2
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
41 - 43 - 47
(a - b)(a + b)

5. Factor x^2 - xy + x.
48
1 & 37/132
x(x - y + 1)
Indeterminable.

6. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
Triangles with same measure and same side lengths.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
13pi / 2
87.5%

7. Which quandrant is the lower right hand?
IV
37.5%
2.592 kg
The greatest value minus the smallest.

8. 0^0
(a - b)(a + b)
Undefined
6
7 / 1000

9. What is the sum of the angles of a triangle?
180 degrees
(a + b)^2
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
72

10. 413.03 x 10^(-4) =
Ax^2 + bx + c where a -b and c are constants and a /=0
A = pi(r^2)
413.03 / 10^4 (move the decimal point 4 places to the left)
F(x + c)

11. 4.809 X 10^7 =
11 - 13 - 17 - 19
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
10! / (10-3)! = 720
.0004809 X 10^11

12. What is a set with no members called?
An isosceles right triangle.
7 / 1000
The empty set - denoted by a circle with a diagonal through it.
1:sqrt3:2

13. Solve the quadratic equation ax^2 + bx + c= 0
10! / (10-3)! = 720
A reflection about the origin.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
11 - 13 - 17 - 19

14. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
A circle centered on the origin with radius 8.
9 & 6/7
1
A tangent is a line that only touches one point on the circumference of a circle.

15. To convert a decimal to a percent...
A grouping of the members within a set based on a shared characteristic.
...multiply by 100.
3
Even

16. Which quadrant is the upper right hand?
I
(a + b)^2
441000 = 1 10 10 10 21 * 21
Triangles with same measure and same side lengths.

17. What is the ratio of the sides of a 30-60-90 triangle?
An angle which is supplementary to an interior angle.
8
1:sqrt3:2
52

18. How to find the diagonal of a rectangular solid?
...multiply by 100.
A circle centered at -2 - -2 with radius 3.
N! / (k!)(n-k)!
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

19. The perimeter of a square is 48 inches. The length of its diagonal is:
The steeper the slope.
12sqrt2
A reflection about the axis.
5

20. (12sqrt15) / (2sqrt5) =
III
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
67 - 71 - 73
F(x) + c

21. What is the measure of an exterior angle of a regular pentagon?
72
...multiply by 100.
12sqrt2
A = pi(r^2)

22. 1/6 in percent?
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
20.5
16.6666%
(a + b)^2

23. 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?
0
75:11
500
288 (8 9 4)

24. 20<all primes<30
8
23 - 29
Even
x= (1.2)(.8)lw

25. Simplify the expression [(b^2 - c^2) / (b - c)]
441000 = 1 10 10 10 21 * 21
The overlapping sections.
(b + c)
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

26. What is a tangent?
48
90
A tangent is a line that only touches one point on the circumference of a circle.
(amount of increase/original price) x 100%

27. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
An isosceles right triangle.
10! / 3!(10-3)! = 120
F(x) - c
Move the decimal point to the right x places

28. 3/8 in percent?
52
53 - 59
True
37.5%

29. Max and Min lengths for a side of a triangle?
Part = Percent X Whole
The third side is greater than the difference and less than the sum.
Its last two digits are divisible by 4.
The sum of digits is divisible by 9.

30. 5x^2 - 35x -55 = 0
Pi is the ratio of a circle'S circumference to its diameter.
1
83.333%
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]

31. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
Part = Percent X Whole
70
The shortest arc between points A and B on a circle'S diameter.
28. n = 8 - k = 2. n! / k!(n-k)!

32. What is the 'Solution' for a system of linear equations?
III
The point of intersection of the systems.
An infinite set.
(a - b)(a + b)

33. Describe the relationship between 3x^2 and 3(x - 1)^2
Even
The set of elements which can be found in either A or B.
(amount of decrease/original price) x 100%
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

34. How many 3-digit positive integers are even and do not contain the digit 4?
2sqrt6
288 (8 9 4)
10! / 3!(10-3)! = 120
A set with no members - denoted by a circle with a diagonal through it.

35. 8.84 / 5.2
(a - b)(a + b)
10! / (10-3)! = 720
Pi is the ratio of a circle'S circumference to its diameter.
1.7

36. What is an exterior angle?
An angle which is supplementary to an interior angle.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
1/a^6
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

37. 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?
Move the decimal point to the right x places
When the function is not defined for all real numbers -; only a subset of the real numbers.
A = pi(r^2)
500

38. What is the graph of f(x) shifted upward c units or spaces?
A circle centered at -2 - -2 with radius 3.
...multiply by 100.
F(x) + c
(n-2) x 180

39. What is a subset?
N! / (k!)(n-k)!
A grouping of the members within a set based on a shared characteristic.
(a - b)^2
The curve opens upward and the vertex is the minimal point on the graph.

40. Convert 0.7% to a fraction.
7 / 1000
55%
Ax^2 + bx + c where a -b and c are constants and a /=0
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)

41. Order of quadrants:
When the function is not defined for all real numbers -; only a subset of the real numbers.
413.03 / 10^4 (move the decimal point 4 places to the left)
From northeast - counterclockwise. I - II - III - IV
20.5

42. What is the ratio of the sides of an isosceles right triangle?
Area of the base X height = (pi)hr^2
1:1:sqrt2
1.0843 X 10^11
A circle centered at -2 - -2 with radius 3.

43. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
11 - 13 - 17 - 19
2sqrt6
The set of elements found in both A and B.
Pi is the ratio of a circle'S circumference to its diameter.

44. What is the absolute value function?
G(x) = {x}
0
x= (1.2)(.8)lw
1.7

45. What are the real numbers?
23 - 29
90 degrees
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)
Undefined

46. What is a parabola?
Triangles with same measure and same side lengths.
4a^2(b)
Ax^2 + bx + c where a -b and c are constants and a /=0
413.03 / 10^4 (move the decimal point 4 places to the left)

47. (-1)^3 =
55%
x= (1.2)(.8)lw
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
1

48. When the 'a' in a parabola is positive....
An expression with just one term (-6x - 2a^2)
53 - 59
The curve opens upward and the vertex is the minimal point on the graph.
6

49. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
x(x - y + 1)
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
A circle centered at -2 - -2 with radius 3.
x^(4+7) = x^11

50. Length of an arc of a circle?
Angle/360 x 2(pi)r
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
27^(-4)
A circle centered at -2 - -2 with radius 3.