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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. Define a 'monomial'
An expression with just one term (-6x - 2a^2)
True
10! / (10-3)! = 720
5

2. x^4 + x^7 =
x^(4+7) = x^11
Two angles whose sum is 90.
An isosceles right triangle.
(a - b)^2

3. The perimeter of a square is 48 inches. The length of its diagonal is:
12sqrt2
(base*height) / 2
G(x) = {x}
6

4. How many multiples does a given number have?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
Angle/360 x 2(pi)r
Infinite.
1

5. What is the formula for compounded interest?
500
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 objects within a set.
A circle centered on the origin with radius 8.

6. 0^0
2
Sector area = (n/360) X (pi)r^2
Undefined
2(pi)r^2 + 2(pi)rh

7. x^2 = 9. What is the value of x?
A tangent is a line that only touches one point on the circumference of a circle.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
3 - -3
12sqrt2

8. Surface area for a cylinder?
2(pi)r^2 + 2(pi)rh
9 : 25
Area of the base X height = (pi)hr^2
(n-2) x 180

9. Factor x^2 - xy + x.
x(x - y + 1)
No - only like radicals can be added.
(n-2) x 180
3/2 - 5/3

10. Simplify the expression (p^2 - q^2)/ -5(q - p)
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
70
(p + q)/5
$3 -500 in the 9% and $2 -500 in the 7%.

11. 8.84 / 5.2
1.7
500
A subset.
F(x) + c

12. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
N! / (k!)(n-k)!
The set of output values for a function.
90
1/(x^y)

13. How to find the area of a sector?
288 (8 9 4)
$11 -448
180 degrees
Angle/360 x (pi)r^2

14. Whats the difference between factors and multiples?
72
130pi
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
Factors are few - multiples are many.

15. Describe the relationship between the graphs of x^2 and (1/2)x^2
Its negative reciprocal. (-b/a)
A subset.
The second graph is less steep.
A reflection about the axis.

16. What are the smallest three prime numbers greater than 65?
A grouping of the members within a set based on a shared characteristic.
90pi
4.25 - 6 - 22
67 - 71 - 73

17. 413.03 x 10^(-4) =
413.03 / 10^4 (move the decimal point 4 places to the left)
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
x^(2(4)) =x^8 = (x^4)^2
A 30-60-90 triangle.

18. What is the maximum value for the function g(x) = (-2x^2) -1?
10
62.5%
20.5
1

19. Which is greater? 64^5 or 16^8
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
75:11
23 - 29
Yes. [i.e. f(x) = x^2 - 1

20. What does the graph x^2 + y^2 = 64 look like?
A circle centered on the origin with radius 8.
10! / 3!(10-3)! = 120
Angle/360 x 2(pi)r
3sqrt4

21. Reduce: 4.8 : 0.8 : 1.6
x^(4+7) = x^11
1
9 & 6/7
6 : 1 : 2

22. What is the formula for computing simple interest?
N! / (k!)(n-k)!
A = I (1 + rt)
Divide by 100.
48

23. What is the 'union' of A and B?
13pi / 2
2(pi)r^2 + 2(pi)rh
The set of elements which can be found in either A or B.
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.

24. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
2 & 3/7
Indeterminable.
y = (x + 5)/2
9 : 25

25. What is a chord of a circle?
1
Its last two digits are divisible by 4.
An arc is a portion of a circumference of a circle.
A chord is a line segment joining two points on a circle.

26. Is 0 even or odd?
2sqrt6
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
Its divisible by 2 and by 3.
Even

27. Simplify the expression [(b^2 - c^2) / (b - c)]
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)
Arc length = (n/360) x pi(2r) where n is the number of degrees.
(b + c)
The overlapping sections.

28. A cylinder has a surface area of 22pi. If the cylinder has a height of 10 - what is the radius?
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.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
0
1

29. What is the 'Range' of a function?
70
F(x) + c
The set of output values for a function.
9 & 6/7

30. The number of degrees in the largest angle of a triangle inscribed in a circle - in which the diameter of the circle is one side of the triangle.
1
Relationship cannot be determined (what if x is negative?)
90 degrees
The point of intersection of the systems.

31. What is the side length of an equilateral triangle with altitude 6?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
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...
Undefined - because we can'T divide by 0.
2.592 kg

32. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
53 - 59
2^9 / 2 = 256
Triangles with same measure and same side lengths.
1

33. What is a parabola?
Sector area = (n/360) X (pi)r^2
Ax^2 + bx + c where a -b and c are constants and a /=0
9 : 25
F(x-c)

34. 4.809 X 10^7 =
The set of elements found in both A and B.
.0004809 X 10^11
Relationship cannot be determined (what if x is negative?)
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

35. What are the real numbers?
A = I (1 + rt)
Two angles whose sum is 180.
23 - 29
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)

36. Can the output value of a function have more than one input value?
... the square of the ratios of the corresponding sides.
(a - b)^2
10
Yes. [i.e. f(x) = x^2 - 1

37. What is the ratio of the sides of an isosceles right triangle?
From northeast - counterclockwise. I - II - III - IV
C = 2(pi)r
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.
1:1:sqrt2

38. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
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)
180 degrees
A circle centered at -2 - -2 with radius 3.
(amount of decrease/original price) x 100%

39. 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?
Yes. [i.e. f(x) = x^2 - 1
(a - b)(a + b)
The second graph is less steep.
y = 2x^2 - 3

40. What is the 'Solution' for a system of linear equations?
An angle which is supplementary to an interior angle.
The point of intersection of the systems.
Its divisible by 2 and by 3.
Undefined - because we can'T divide by 0.

41. What is the sum of the angles of a triangle?
67 - 71 - 73
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
180 degrees
Diameter(Pi)

42. What are 'Supplementary angles?'
The curve opens upward and the vertex is the minimal point on the graph.
1:1:sqrt2
Two angles whose sum is 180.
F(x-c)

43. A number is divisible by 4 is...
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
1/a^6
90pi
Its last two digits are divisible by 4.

44. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
A 30-60-90 triangle.
83.333%
7 / 1000
All numbers multiples of 1.

45. Evaluate (4^3)^2
4096
1
The sum of digits is divisible by 9.
12sqrt2

46. Can you subtract 3sqrt4 from sqrt4?
Yes - like radicals can be added/subtracted.
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
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
5

47. Formula for the area of a sector of a circle?
Sector area = (n/360) X (pi)r^2
18
Infinite.
Sqrt 12

48. Employee X is paid 19.50 per hour no matter how many a week. Employee Y earns 18 for the first 40 and 1.5 the hourly wage for every hour after that. If both earned the same amount and worked the same in one week - how many did each work?
48
1
Infinite.
2^9 / 2 = 256

49. What is the 'Solution' for a set of inequalities.
The overlapping sections.
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)
2(pi)r^2 + 2(pi)rh
(b + c)

50. Factor a^2 + 2ab + b^2
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The shortest arc between points A and B on a circle'S diameter.
(a + b)^2
x^(4+7) = x^11