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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 are complementary angles?
Two angles whose sum is 90.
The overlapping sections.
Angle/360 x 2(pi)r
C = (pi)d

2. 6w^2 - w - 15 = 0
1
3/2 - 5/3
27^(-4)
4725

3. Legs 6 - 8. Hypotenuse?
10
$3 -500 in the 9% and $2 -500 in the 7%.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
1/(x^y)

4. Formula for the area of a circle?
Divide by 100.
A = pi(r^2)
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
413.03 / 10^4 (move the decimal point 4 places to the left)

5. What is the intersection of A and B?
7 / 1000
48
The set of elements found in both A and B.
(amount of increase/original price) x 100%

6. x^2 = 9. What is the value of x?
3 - -3
The curve opens upward and the vertex is the minimal point on the graph.
Area of the base X height = (pi)hr^2
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

7. Formula to find a circle'S circumference from its diameter?
4725
The third side is greater than the difference and less than the sum.
C = (pi)d
When the function is not defined for all real numbers -; only a subset of the real numbers.

8. Solve the quadratic equation ax^2 + bx + c= 0
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
An arc is a portion of a circumference of a circle.
4:5
The steeper the slope.

9. Formula for the area of a sector of a circle?
Diameter(Pi)
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
Sector area = (n/360) X (pi)r^2
The second graph is less steep.

10. 2sqrt4 + sqrt4 =
Sector area = (n/360) X (pi)r^2
5 OR -5
3sqrt4
$3 -500 in the 9% and $2 -500 in the 7%.

11. When the 'a' in a parabola is positive....
The objects within a set.
1
The curve opens upward and the vertex is the minimal point on the graph.
The empty set - denoted by a circle with a diagonal through it.

12. Simplify (a^2 + b)^2 - (a^2 - b)^2
Factors are few - multiples are many.
3
4a^2(b)
61 - 67

13. (-1)^2 =
Yes - like radicals can be added/subtracted.
IV
1
3/2 - 5/3

14. What is a finite set?
A set with a number of elements which can be counted.
The sum of its digits is divisible by 3.
(amount of decrease/original price) x 100%
2^9 / 2 = 256

15. 413.03 x 10^(-4) =
413.03 / 10^4 (move the decimal point 4 places to the left)
71 - 73 - 79
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
90 degrees

16. Ratio of ages of Anna and Emma is 3:5 and of Emma and Nicolas is 3:5. What is the ratio of Anna to Nicholas' ages?
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
9 : 25
An arc is a portion of a circumference of a circle.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

17. x^(-y)=
1/(x^y)
No - the input value has exactly one output.
Area of the base X height = (pi)hr^2
True

18. What number between 70 & 75 - inclusive - has the greatest number of factors?
(amount of decrease/original price) x 100%
When the function is not defined for all real numbers -; only a subset of the real numbers.
4725
72

19. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
The longest arc between points A and B on a circle'S diameter.
28. n = 8 - k = 2. n! / k!(n-k)!
3
y = (x + 5)/2

20. 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?
Two angles whose sum is 180.
75:11
The longest arc between points A and B on a circle'S diameter.
4a^2(b)

21. What is the 'Solution' for a set of inequalities.
The overlapping sections.
75:11
0
20.5

22. Area of a triangle?
(base*height) / 2
y = 2x^2 - 3
Two angles whose sum is 90.
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

23. What is the graph of f(x) shifted downward c units or spaces?
72
Sector area = (n/360) X (pi)r^2
F(x) - c
441000 = 1 10 10 10 21 * 21

24. Can the input value of a function have more than one output value (i.e. x: y - y1)?
No - the input value has exactly one output.
9 : 25
2sqrt6
x^(6-3) = x^3

25. 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
20.5
12.5%
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

26. What is the graph of f(x) shifted left c units or spaces?
The greatest value minus the smallest.
83.333%
2 & 3/7
F(x + c)

27. How many 3-digit positive integers are even and do not contain the digit 4?
F(x + c)
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
288 (8 9 4)
Undefined - because we can'T divide by 0.

28. 40 < all primes<50
41 - 43 - 47
3/2 - 5/3
F(x) + c
5

29. What is an exterior angle?
10! / 3!(10-3)! = 120
An angle which is supplementary to an interior angle.
The overlapping sections.
A circle centered at -2 - -2 with radius 3.

30. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
4:5
x= (1.2)(.8)lw
55%
3

31. What does scientific notation mean?
A set with a number of elements which can be counted.
II
The point of intersection of the systems.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

32. What are the rational numbers?
72
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
From northeast - counterclockwise. I - II - III - IV
11 - 13 - 17 - 19

33. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
An isosceles right triangle.
70
The steeper the slope.
500

34. Simplify the expression [(b^2 - c^2) / (b - c)]
Sqrt 12
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
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
(b + c)

35. What is the formula for compounded interest?
$11 -448
$3 -500 in the 9% and $2 -500 in the 7%.
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.
288 (8 9 4)

36. Suppose that the graph of f(x) is the result of stretching y=x + 5 away from the x-axis by a factor of 2. What is the new equation for the graph f(x)?
A reflection about the axis.
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
y = (x + 5)/2
Its last two digits are divisible by 4.

37. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
2
2(pi)r^2 + 2(pi)rh
Ax^2 + bx + c where a -b and c are constants and a /=0
31 - 37

38. What are congruent triangles?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
61 - 67
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
Triangles with same measure and same side lengths.

39. What is a set with no members called?
1
The empty set - denoted by a circle with a diagonal through it.
Two angles whose sum is 180.
An isosceles right triangle.

40. What is the area of a regular hexagon with side 6?
Cd
5 OR -5
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

41. 25^(1/2) or sqrt. 25 =
A circle centered on the origin with radius 8.
A = I (1 + rt)
Relationship cannot be determined (what if x is negative?)
5 OR -5

42. What is the surface area of a cylinder with radius 5 and height 8?
The curve opens downward and the vertex is the maximum point on the graph.
130pi
(amount of increase/original price) x 100%
Move the decimal point to the right x places

43. When the 'a' in the parabola is negative...
10! / (10-3)! = 720
The curve opens downward and the vertex is the maximum point on the graph.
10
72

44. A company places a 6-symbol code on each product. The code consists of the letter T - followed by 3 numerical digits - and then 2 consonants (Y is a conson). How many codes are possible?
441000 = 1 10 10 10 21 * 21
A set with no members - denoted by a circle with a diagonal through it.
52
13

45. Which quadrant is the upper right hand?
An expression with just one term (-6x - 2a^2)
I
A grouping of the members within a set based on a shared characteristic.
5

46. 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?
1
6 : 1 : 2
10! / 3!(10-3)! = 120
(amount of increase/original price) x 100%

47. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
6
Indeterminable.

48. a^2 - b^2 =
A grouping of the members within a set based on a shared characteristic.
Members or elements
(a - b)(a + b)
441000 = 1 10 10 10 21 * 21

49. Volume for a cylinder?
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
52
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Area of the base X height = (pi)hr^2

50. 1/8 in percent?
A subset.
A set with no members - denoted by a circle with a diagonal through it.
12.5%
Cd