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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 the smallest three prime numbers greater than 65?
Two angles whose sum is 90.
1:sqrt3:2
4096
67 - 71 - 73

2. Circumference of a circle?
Diameter(Pi)
8
A tangent is a line that only touches one point on the circumference of a circle.
When the function is not defined for all real numbers -; only a subset of the real numbers.

3. What are the real numbers?
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)
x^(6-3) = x^3
9 : 25
The second graph is less steep.

4. Legs 5 - 12. Hypotenuse?
An angle which is supplementary to an interior angle.
4096
13
2

5. What transformation occurs if point C is reflected over the x-axis and then the y-axis?
An isosceles right triangle.
6
413.03 / 10^4 (move the decimal point 4 places to the left)
A reflection about the axis.

6. Evaluate 4/11 + 11/12
1 & 37/132
90pi
1
The longest arc between points A and B on a circle'S diameter.

7. Surface area for a cylinder?
An arc is a portion of a circumference of a circle.
2(pi)r^2 + 2(pi)rh
x^(4+7) = x^11
Its negative reciprocal. (-b/a)

8. Describe the relationship between the graphs of x^2 and (1/2)x^2
The second graph is less steep.
Divide by 100.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
6

9. Suppose that the graph of f(x) is the result of sliding the graph of y=2x^2 down 3 units of spaces. What is the new equation?
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
y = 2x^2 - 3
41 - 43 - 47
12! / 5!7! = 792

10. To multiply a number by 10^x
A = pi(r^2)
(b + c)
Move the decimal point to the right x places
1

11. The larger the absolute value of the slope...
1.0843 X 10^11
The steeper the slope.
Relationship cannot be determined (what if x is negative?)
Sqrt 12

12. What are congruent triangles?
Triangles with same measure and same side lengths.
Two angles whose sum is 90.
$3 -500 in the 9% and $2 -500 in the 7%.
23 - 29

13. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
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 - b)(a + b)
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
3

14. x^(-y)=
A reflection about the origin.
55%
F(x) - c
1/(x^y)

15. Can you add sqrt 3 and sqrt 5?
5 OR -5
$3 -500 in the 9% and $2 -500 in the 7%.
No - only like radicals can be added.
5

16. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
(a - b)(a + b)
No - the input value has exactly one output.
28. n = 8 - k = 2. n! / k!(n-k)!
2

17. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
2(pi)r^2 + 2(pi)rh
8
Ax^2 + bx + c where a -b and c are constants and a /=0
An arc is a portion of a circumference of a circle.

18. Formula to find a circle'S circumference from its radius?
C = 2(pi)r
Two angles whose sum is 90.
$11 -448
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.

19. What are complementary angles?
1/2 times 7/3
180 degrees
Two angles whose sum is 90.
90 degrees

20. What is the 'Restricted domain of a function'?
180 degrees
Two angles whose sum is 180.
When the function is not defined for all real numbers -; only a subset of the real numbers.
10

21. Which quandrant is the lower right hand?
5 OR -5
N! / (k!)(n-k)!
An infinite set.
IV

22. What is the graph of f(x) shifted downward c units or spaces?
(a + b)^2
F(x) - c
Lies opposite the greater angle
A 30-60-90 triangle.

23. Convert 0.7% to a fraction.
7 / 1000
(a + b)^2
Pi is the ratio of a circle'S circumference to its diameter.
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

24. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
4725
67 - 71 - 73
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

25. Can the output value of a function have more than one input value?
1
3sqrt4
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)
Yes. [i.e. f(x) = x^2 - 1

26. A number is divisible by 4 is...
6 : 1 : 2
4096
A = pi(r^2)
Its last two digits are divisible by 4.

27. What is an isoceles triangle?
An expression with just one term (-6x - 2a^2)
Two equal sides and two equal angles.
18
6 : 1 : 2

28. How to find the area of a sector?
72
13pi / 2
53 - 59
Angle/360 x (pi)r^2

29. What is the graph of f(x) shifted right c units or spaces?
0
288 (8 9 4)
48
F(x-c)

30. 50 < all primes< 60
53 - 59
2.592 kg
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)
Sqrt 12

31. What is the set of elements which can be found in either A or B?
71 - 73 - 79
The union of A and B.
The curve opens upward and the vertex is the minimal point on the graph.
The set of elements which can be found in either A or B.

32. Factor x^2 - xy + x.
10! / (10-3)! = 720
An isosceles right triangle.
x(x - y + 1)
A central angle is an angle formed by 2 radii.

33. 10<all primes<20
The empty set - denoted by a circle with a diagonal through it.
11 - 13 - 17 - 19
An arc is a portion of a circumference of a circle.
75:11

34. What is the 'Solution' for a system of linear equations?
(a - b)(a + b)
Triangles with same measure and same side lengths.
The point of intersection of the systems.
F(x-c)

35. Which quadrant is the lower left hand?
The greatest value minus the smallest.
23 - 29
III
x= (1.2)(.8)lw

36. When the 'a' in the parabola is negative...
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
The curve opens downward and the vertex is the maximum point on the graph.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
0

37. 0^0
An infinite set.
Sector area = (n/360) X (pi)r^2
Its last two digits are divisible by 4.
Undefined

38. A number is divisible by 9 if...
3sqrt4
The sum of digits is divisible by 9.
Pi is the ratio of a circle'S circumference to its diameter.
x^(2(4)) =x^8 = (x^4)^2

39. 30< all primes<40
Diameter(Pi)
28. n = 8 - k = 2. n! / k!(n-k)!
Its divisible by 2 and by 3.
31 - 37

40. 10^6 has how many zeroes?
31 - 37
The two xes after factoring.
Factors are few - multiples are many.
6

41. What is a set with no members called?
A = pi(r^2)
The empty set - denoted by a circle with a diagonal through it.
Pi is the ratio of a circle'S circumference to its diameter.
Lies opposite the greater angle

42. Solve the quadratic equation ax^2 + bx + c= 0
Area of the base X height = (pi)hr^2
61 - 67
4725
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

43. What is a piecewise equation?
Undefined
F(x + c)
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
The third side is greater than the difference and less than the sum.

44. 25^(1/2) or sqrt. 25 =
II
4a^2(b)
(amount of decrease/original price) x 100%
5 OR -5

45. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
A chord is a line segment joining two points on a circle.
The set of elements which can be found in either A or B.
The objects within a set.
A 30-60-90 triangle.

46. 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)?
71 - 73 - 79
y = (x + 5)/2
10
10! / (10-3)! = 720

47. What is the percent formula?
Yes - like radicals can be added/subtracted.
Part = Percent X Whole
The set of elements found in both A and B.
288 (8 9 4)

48. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
4a^2(b)
10! / (10-3)! = 720
F(x) + c
2sqrt6

49. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
12.5%
The union of A and B.
Cd
9 : 25

50. 5x^2 - 35x -55 = 0
...multiply by 100.
90
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The set of output values for a function.