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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. Reduce: 4.8 : 0.8 : 1.6
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...
31 - 37
F(x-c)
6 : 1 : 2

2. 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?
y = 2x^2 - 3
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
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
6

3. A number is divisible by 3 if ...
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.
Two equal sides and two equal angles.
1
The sum of its digits is divisible by 3.

4. Convert 0.7% to a fraction.
7 / 1000
.0004809 X 10^11
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.
37.5%

5. If a=-1 and b=3 - what is the value of (4(a^3)(b^2) - 12(a^2)(b^5)) / (16(a^3)(b^2))?
23 - 29
6
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
20.5

6. 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?
288 (8 9 4)
61 - 67
N! / (k!)(n-k)!
x= (1.2)(.8)lw

7. 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?
(p + q)/5
75:11
The sum of digits is divisible by 9.
(a - b)(a + b)

8. What is an isoceles triangle?
3sqrt4
Two equal sides and two equal angles.
3 - -3
7 / 1000

9. What is the intersection of A and B?
The set of elements found in both A and B.
Pi is the ratio of a circle'S circumference to its diameter.
5 OR -5
III

10. Legs: 3 - 4. Hypotenuse?
An expression with just one term (-6x - 2a^2)
x(x - y + 1)
(a + b)^2
5

11. What are the roots of the quadrinomial x^2 + 2x + 1?
4:5
Its negative reciprocal. (-b/a)
The two xes after factoring.
An expression with just one term (-6x - 2a^2)

12. What is a minor arc?

13. Formula to find a circle'S circumference from its radius?
Part = Percent X Whole
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
C = 2(pi)r
87.5%

14. Is 0 even or odd?
3/2 - 5/3
180
Even
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

15. What is the 'Restricted domain of a function'?
(a - b)(a + b)
When the function is not defined for all real numbers -; only a subset of the real numbers.
90 degrees
The set of elements found in both A and B.

16. What is the empty set?
A set with no members - denoted by a circle with a diagonal through it.
F(x-c)
83.333%
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

17. 1/2 divided by 3/7 is the same as
Factors are few - multiples are many.
28. n = 8 - k = 2. n! / k!(n-k)!
A central angle is an angle formed by 2 radii.
1/2 times 7/3

18. Describe the relationship between 3x^2 and 3(x - 1)^2
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
(amount of decrease/original price) x 100%
6 : 1 : 2
N! / (k!)(n-k)!

19. Can you add sqrt 3 and sqrt 5?
No - only like radicals can be added.
An arc is a portion of a circumference of a circle.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
(a - b)^2

20. x^2 = 9. What is the value of x?
A subset.
62.5%
An arc is a portion of a circumference of a circle.
3 - -3

21. 10<all primes<20
F(x) + c
11 - 13 - 17 - 19
28. n = 8 - k = 2. n! / k!(n-k)!
A circle centered at -2 - -2 with radius 3.

22. Evaluate 4/11 + 11/12
1 & 37/132
A grouping of the members within a set based on a shared characteristic.
(b + c)
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

23. Can the input value of a function have more than one output value (i.e. x: y - y1)?
A reflection about the axis.
x(x - y + 1)
No - the input value has exactly one output.
2.592 kg

24. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
1/(x^y)
A central angle is an angle formed by 2 radii.
12! / 5!7! = 792
Move the decimal point to the right x places

25. 2sqrt4 + sqrt4 =
75:11
72
3sqrt4
A reflection about the origin.

26. What is the percent formula?
3/2 - 5/3
Part = Percent X Whole
Undefined
41 - 43 - 47

27. What is the 'Solution' for a system of linear equations?
The point of intersection of the systems.
The sum of digits is divisible by 9.
70
A subset.

28. What are the integers?
(p + q)/5
12! / 5!7! = 792
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
All numbers multiples of 1.

29. To multiply a number by 10^x
Two equal sides and two equal angles.
(amount of increase/original price) x 100%
Move the decimal point to the right x places
53 - 59

30. In a regular polygon with n sides - the formula for the sum of interior angles
70
(n-2) x 180
The objects within a set.
(a + b)^2

31. sqrt 2(sqrt 6)=
10
Sqrt 12
2
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

32. What are 'Supplementary angles?'
A circle centered at -2 - -2 with radius 3.
Two angles whose sum is 180.
The set of output values for a function.
8

33. What percent of 40 is 22?
1
(base*height) / 2
55%
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

34. 6w^2 - w - 15 = 0
The point of intersection of the systems.
2.592 kg
A reflection about the origin.
3/2 - 5/3

35. Max and Min lengths for a side of a triangle?
(a - b)(a + b)
7 / 1000
The third side is greater than the difference and less than the sum.
13

36. Whats the difference between factors and multiples?
F(x) - c
Infinite.
Factors are few - multiples are many.
The two xes after factoring.

37. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
(a - b)(a + b)
2 & 3/7
x= (1.2)(.8)lw
18

38. x^4 + x^7 =
F(x) + c
Angle/360 x (pi)r^2
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
x^(4+7) = x^11

39. (-1)^2 =
6 : 1 : 2
1
3
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

40. The objects in a set are called two names:
180 degrees
13
Members or elements
N! / (k!)(n-k)!

41. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
413.03 / 10^4 (move the decimal point 4 places to the left)
Yes - like radicals can be added/subtracted.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
N! / (n-k)!

42. Describe the relationship between the graphs of x^2 and (1/2)x^2
5 OR -5
The second graph is less steep.
2sqrt6
Yes. [i.e. f(x) = x^2 - 1

43. What is the graph of f(x) shifted left c units or spaces?
x^(2(4)) =x^8 = (x^4)^2
F(x + c)
2^9 / 2 = 256
The set of elements which can be found in either A or B.

44. 5/6 in percent?
83.333%
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

45. A number is divisible by 6 if...
The empty set - denoted by a circle with a diagonal through it.
Factors are few - multiples are many.
Its divisible by 2 and by 3.
The overlapping sections.

46. 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?
Part = Percent X Whole
(p + q)/5
9 : 25
(a + b)^2

47. x^6 / x^3
12sqrt2
Diameter(Pi)
(a - b)(a + b)
x^(6-3) = x^3

48. When the 'a' in a parabola is positive....
2sqrt6
A circle centered on the origin with radius 8.
72
The curve opens upward and the vertex is the minimal point on the graph.

49. Factor a^2 + 2ab + b^2
A chord is a line segment joining two points on a circle.
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
An expression with just one term (-6x - 2a^2)
(a + b)^2

50. How many 3-digit positive integers are even and do not contain the digit 4?
288 (8 9 4)
A = I (1 + rt)
y = (x + 5)/2
0