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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. 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
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...
10

2. Formula for the area of a sector of a circle?
Sector area = (n/360) X (pi)r^2
2 & 3/7
A central angle is an angle formed by 2 radii.
The second graph is less steep.

3. 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?
Move the decimal point to the right x places
75:11
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)

4. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
4a^2(b)
Two angles whose sum is 90.
90
5 OR -5

5. To convert a decimal to a percent...
413.03 / 10^4 (move the decimal point 4 places to the left)
An infinite set.
The overlapping sections.
...multiply by 100.

6. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
90 degrees
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
Cd
16.6666%

7. 25^(1/2) or sqrt. 25 =
Relationship cannot be determined (what if x is negative?)
8
20.5
5 OR -5

8. A number is divisible by 3 if ...
55%
4096
0
The sum of its digits is divisible by 3.

9. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
x^(6-3) = x^3
8
The sum of digits is divisible by 9.
4096

10. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
A set with a number of elements which can be counted.
$11 -448
No - the input value has exactly one output.
When the function is not defined for all real numbers -; only a subset of the real numbers.

11. What percent of 40 is 22?
55%
72
1.0843 X 10^11
A circle centered on the origin with radius 8.

12. What is the graph of f(x) shifted downward c units or spaces?
III
F(x) - c
Part = Percent X Whole
Pi is the ratio of a circle'S circumference to its diameter.

13. What is the graph of f(x) shifted left c units or spaces?
F(x + c)
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
A circle centered on the origin with radius 8.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

14. A number is divisible by 4 is...
A circle centered on the origin with radius 8.
8
Its last two digits are divisible by 4.
The steeper the slope.

15. How to determine percent decrease?
(amount of decrease/original price) x 100%
83.333%
12.5%
72

16. What is the 'Solution' for a set of inequalities.
True
An angle which is supplementary to an interior angle.
A central angle is an angle formed by 2 radii.
The overlapping sections.

17. The ratio of the areas of two similar polygons is ...
... the square of the ratios of the corresponding sides.
Indeterminable.
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
(a + b)^2

18. 50 < all primes< 60
1.7
53 - 59
A set with no members - denoted by a circle with a diagonal through it.
Arc length = (n/360) x pi(2r) where n is the number of degrees.

19. Order of quadrants:
From northeast - counterclockwise. I - II - III - IV
1.7
500
2(pi)r^2 + 2(pi)rh

20. What is the formula for computing simple interest?
A = I (1 + rt)
2 & 3/7
9 : 25
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

21. What is the set of elements found in both A and B?
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)
20.5
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...
The interesection of A and B.

22. 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?
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)
2.592 kg
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
(a + b)^2

23. 0^0
x(x - y + 1)
83.333%
Undefined
Lies opposite the greater angle

24. Legs: 3 - 4. Hypotenuse?
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
5
Angle/360 x (pi)r^2
Members or elements

25. Which quandrant is the lower right hand?
IV
A term is a numerical constant or the product (or quotient) of a numerical constant and one or more variables. (3x - 4x^2 and 2a/c)
The direction of the inequality is reversed.
From northeast - counterclockwise. I - II - III - IV

26. a^0 =
Divide by 100.
Diameter(Pi)
Even
1

27. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
8
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
A circle centered at -2 - -2 with radius 3.

28. a^2 + 2ab + b^2
(a + b)^2
83.333%
Ax^2 + bx + c where a -b and c are constants and a /=0
A reflection about the origin.

29. 30< all primes<40
31 - 37
72
Part = Percent X Whole
y = 2x^2 - 3

30. Can the output value of a function have more than one input value?
Yes. [i.e. f(x) = x^2 - 1
23 - 29
87.5%
4a^2(b)

31. What is an isoceles triangle?
The direction of the inequality is reversed.
Sector area = (n/360) X (pi)r^2
Two equal sides and two equal angles.
Diameter(Pi)

32. For similar triangles - the ratio of their corresponding sides is 2:3. What is the ratio of their areas?
.0004809 X 10^11
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
The overlapping sections.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.

33. 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)
4a^2(b)
4.25 - 6 - 22
Indeterminable.
3

34. Suppose you have a set of n objects - and you want to select k of them - but the order doesn'T matter. What formula do you use to determine the number of combinations of n objects taken k at a time?
N! / (k!)(n-k)!
4.25 - 6 - 22
1/a^6
2

35. If the 80th percentile of the measurements is 72degrees - about how many measurments are between 69 degrees and 72 degrees? Round your answer to the nearest tenth
4725
18
Cd
2^9 / 2 = 256

36. Can the input value of a function have more than one output value (i.e. x: y - y1)?
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
No - the input value has exactly one output.
The steeper the slope.
23 - 29

37. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
A tangent is a line that only touches one point on the circumference of a circle.
Move the decimal point to the right x places
I
A reflection about the origin.

38. What is the sum of the angles of a triangle?
y = 2x^2 - 3
The overlapping sections.
180 degrees
6 : 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?
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
12.5%
48
10! / 3!(10-3)! = 120

40. Can you add sqrt 3 and sqrt 5?
...multiply by 100.
(b + c)
C = (pi)d
No - only like radicals can be added.

41. a^2 - b^2
(a - b)(a + b)
31 - 37
A circle centered at -2 - -2 with radius 3.
12.5%

42. How many sides does a hexagon have?
6
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
Arc length = (n/360) x pi(2r) where n is the number of degrees.
28. n = 8 - k = 2. n! / k!(n-k)!

43. What is the graph of f(x) shifted right c units or spaces?
C = 2(pi)r
Undefined
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)
F(x-c)

44. 5x^2 - 35x -55 = 0
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
3
Part = Percent X Whole
Undefined

45. Evaluate 3& 2/7 / 1/3
9 & 6/7
37.5%
2
The longest arc between points A and B on a circle'S diameter.

46. What is a piecewise equation?
The set of output values for a function.
53 - 59
0
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

47. Formula to find a circle'S circumference from its diameter?
16.6666%
C = (pi)d
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
41 - 43 - 47

48. a^2 - 2ab + b^2
500
6 : 1 : 2
10! / (10-3)! = 720
(a - b)^2

49. How to determine percent increase?
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.
The set of output values for a function.
(amount of increase/original price) x 100%
441000 = 1 10 10 10 21 * 21

50. What is the set of elements which can be found in either A or B?
The union of A and B.
1/a^6
12.5%
Angle/360 x (pi)r^2