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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. Max and Min lengths for a side of a triangle?
The third side is greater than the difference and less than the sum.
37.5%
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
4.25 - 6 - 22

2. 1/2 divided by 3/7 is the same as
31 - 37
1/2 times 7/3
Infinite.
The set of elements which can be found in either A or B.

3. How many sides does a hexagon have?
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
x(x - y + 1)
55%
6

4. (6sqrt3) x (2sqrt5) =
Yes. [i.e. f(x) = x^2 - 1
... the square of the ratios of the corresponding sides.
The set of elements which can be found in either A or B.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

5. What is the side length of an equilateral triangle with altitude 6?
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...
5 OR -5
(amount of decrease/original price) x 100%
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

6. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
52
13pi / 2
(amount of increase/original price) x 100%
1/(x^y)

7. When the 'a' in the parabola is negative...
9 : 25
The curve opens downward and the vertex is the maximum point on the graph.
... the square of the ratios of the corresponding sides.
413.03 / 10^4 (move the decimal point 4 places to the left)

8. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
70
The direction of the inequality is reversed.
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
The point of intersection of the systems.

9. Number of degrees in a triangle
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
1 & 37/132
Angle/360 x (pi)r^2
180

10. 70 < all primes< 80
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 30-60-90 triangle.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
71 - 73 - 79

11. Formula for the area of a sector of a circle?
2 & 3/7
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
Yes. [i.e. f(x) = x^2 - 1
Sector area = (n/360) X (pi)r^2

12. What is a chord of a circle?
A chord is a line segment joining two points on a circle.
x^(6-3) = x^3
Factors are few - multiples are many.
4:5

13. What is a parabola?
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The set of input values for a function.
3
Ax^2 + bx + c where a -b and c are constants and a /=0

14. How many 3-digit positive integers are even and do not contain the digit 4?
288 (8 9 4)
A circle centered on the origin with radius 8.
The direction of the inequality is reversed.
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

15. What is the 'Solution' for a system of linear equations?
Yes - like radicals can be added/subtracted.
The point of intersection of the systems.
The objects within a set.
(p + q)/5

16. 8.84 / 5.2
1.7
(a - b)(a + b)
x(x - y + 1)
1

17. If an inequality is multiplied or divided by a negative number....
III
2 & 3/7
5
The direction of the inequality is reversed.

18. 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
67 - 71 - 73
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)
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.

19. Can you subtract 3sqrt4 from sqrt4?
(p + q)/5
Yes - like radicals can be added/subtracted.
3 - -3
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

20. (x^2)^4
x^(2(4)) =x^8 = (x^4)^2
11 - 13 - 17 - 19
Diameter(Pi)
4.25 - 6 - 22

21. Legs 6 - 8. Hypotenuse?
90pi
10
(a - b)(a + b)
31 - 37

22. What percent of 40 is 22?
$11 -448
A circle centered at -2 - -2 with radius 3.
3
55%

23. The slope of a line perpendicular to (a/b)?
48
Its negative reciprocal. (-b/a)
N! / (n-k)!
1

24. Simplify 9^(1/2) X 4^3 X 2^(-6)?
Infinite.
A tangent is a line that only touches one point on the circumference of a circle.
x^(6-3) = x^3
3

25. Simplify the expression (p^2 - q^2)/ -5(q - p)
The curve opens upward and the vertex is the minimal point on the graph.
(p + q)/5
4725
IV

26. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
0
0
A chord is a line segment joining two points on a circle.
90

27. What is an exterior angle?
87.5%
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
Yes - like radicals can be added/subtracted.
An angle which is supplementary to an interior angle.

28. 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?
71 - 73 - 79
Undefined
9 & 6/7
75:11

29. Surface area for a cylinder?
90pi
2(pi)r^2 + 2(pi)rh
4725
C = (pi)d

30. What is the empty set?
$11 -448
A set with no members - denoted by a circle with a diagonal through it.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
0

31. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
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)
A 30-60-90 triangle.
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).

32. What are the integers?
All numbers multiples of 1.
An arc is a portion of a circumference of a circle.
31 - 37
N! / (k!)(n-k)!

33. What is the name for a grouping of the members within a set based on a shared characteristic?
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.
Yes. [i.e. f(x) = x^2 - 1
6 : 1 : 2
A subset.

34. 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?
1
23 - 29
90
2.592 kg

35. a^2 - b^2 =
(n-2) x 180
(a - b)^2
(a - b)(a + b)
True

36. Circumference of a circle?
True
Diameter(Pi)
A central angle is an angle formed by 2 radii.
The point of intersection of the systems.

37. Can you add sqrt 3 and sqrt 5?
...multiply by 100.
No - only like radicals can be added.
1
A tangent is a line that only touches one point on the circumference of a circle.

38. a^2 - b^2
1/2 times 7/3
(a - b)(a + b)
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
4725

39. 5/8 in percent?
From northeast - counterclockwise. I - II - III - IV
62.5%
III
71 - 73 - 79

40. Length of an arc of a circle?
2
2 & 3/7
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
Angle/360 x 2(pi)r

41. Define an 'expression'.
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)
55%
A = I (1 + rt)
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

42. If r - t - s & u are distinct - consecutive prime numbers - less than 31 - which of the following could be an average of them (4 - 4.25 - 6 - 9 - 24 - 22 - 24)
4.25 - 6 - 22
20.5
1
Indeterminable.

43. 60 < all primes <70
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
The set of input values for a function.
(b + c)
61 - 67

44. Evaluate (4^3)^2
4096
1
.0004809 X 10^11
All numbers multiples of 1.

45. What is a subset?
A = pi(r^2)
A = I (1 + rt)
Two angles whose sum is 180.
A grouping of the members within a set based on a shared characteristic.

46. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
Two equal sides and two equal angles.
II
4:5

47. How to determine percent increase?
The union of A and B.
(amount of increase/original price) x 100%
180
Sector area = (n/360) X (pi)r^2

48. What is the 'Solution' for a set of inequalities.
71 - 73 - 79
The overlapping sections.
20.5
A 30-60-90 triangle.

49. What is the ratio of the sides of a 30-60-90 triangle?
1:sqrt3:2
Two angles whose sum is 180.
x^(6-3) = x^3
I

50. Simplify the expression [(b^2 - c^2) / (b - c)]
Relationship cannot be determined (what if x is negative?)
9 : 25
3
(b + c)