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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. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
(n-2) x 180
4:5
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.
From northeast - counterclockwise. I - II - III - IV

2. Legs: 3 - 4. Hypotenuse?
F(x) + c
F(x-c)
5
A central angle is an angle formed by 2 radii.

3. The slope of a line perpendicular to (a/b)?
83.333%
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)
Its negative reciprocal. (-b/a)
3sqrt4

4. 5/8 in percent?
90
12.5%
62.5%
F(x) + c

5. What percent of 40 is 22?
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...
55%
61 - 67
1

6. a^0 =
Angle/360 x (pi)r^2
31 - 37
1
Pi is the ratio of a circle'S circumference to its diameter.

7. What are the rational numbers?
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
28. n = 8 - k = 2. n! / k!(n-k)!
From northeast - counterclockwise. I - II - III - IV
A central angle is an angle formed by 2 radii.

8. 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.
N! / (k!)(n-k)!
6
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
90 degrees

9. How to find the diagonal of a rectangular solid?
The interesection of A and B.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
The second graph is less steep.
23 - 29

10. Formula to find a circle'S circumference from its diameter?
C = (pi)d
(a - b)(a + b)
Two angles whose sum is 180.
Relationship cannot be determined (what if x is negative?)

11. (-1)^3 =
1:1:sqrt2
1
16.6666%
A central angle is an angle formed by 2 radii.

12. What is the 'Range' of a series of numbers?
2(pi)r^2 + 2(pi)rh
A reflection about the axis.
28. n = 8 - k = 2. n! / k!(n-k)!
The greatest value minus the smallest.

13. 50 < all primes< 60
31 - 37
53 - 59
83.333%
Ax^2 + bx + c where a -b and c are constants and a /=0

14. What is a piecewise equation?
The point of intersection of the systems.
The two xes after factoring.
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 sum of its digits is divisible by 3.

15. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
A set with no members - denoted by a circle with a diagonal through it.
Cd
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
413.03 / 10^4 (move the decimal point 4 places to the left)

16. Can you subtract 3sqrt4 from sqrt4?
Sqrt 12
An infinite set.
Yes - like radicals can be added/subtracted.
2sqrt6

17. For similar triangles - the ratio of their corresponding sides is 2:3. What is the ratio of their areas?
1.0843 X 10^11
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
A chord is a line segment joining two points on a circle.
The second graph is less steep.

18. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
A = I (1 + rt)
23 - 29
$11 -448
7 / 1000

19. What is the formula for computing simple interest?
III
I
A = I (1 + rt)
Angle/360 x (pi)r^2

20. (-1)^2 =
3sqrt4
A = pi(r^2)
1
The union of A and B.

21. If an inequality is multiplied or divided by a negative number....
When the function is not defined for all real numbers -; only a subset of the real numbers.
53 - 59
8
The direction of the inequality is reversed.

22. 0^0
Yes - like radicals can be added/subtracted.
10! / (10-3)! = 720
Undefined
3/2 - 5/3

23. What is a central angle?
41 - 43 - 47
A grouping of the members within a set based on a shared characteristic.
A central angle is an angle formed by 2 radii.
The greatest value minus the smallest.

24. What is the formula for compounded interest?
The shortest arc between points A and B on a circle'S diameter.
y = (x + 5)/2
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.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a

25. What is the 'Solution' for a system of linear equations?
The point of intersection of the systems.
Arc length = (n/360) x pi(2r) where n is the number of degrees.
4:5
An isosceles right triangle.

26. Legs 6 - 8. Hypotenuse?
10
A subset.
2sqrt6
71 - 73 - 79

27. How to determine percent increase?
(amount of increase/original price) x 100%
Area of the base X height = (pi)hr^2
48
From northeast - counterclockwise. I - II - III - IV

28. 2sqrt4 + sqrt4 =
3sqrt4
G(x) = {x}
90 degrees
(n-2) x 180

29. Define an 'expression'.
1
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)^2
2^9 / 2 = 256

30. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
A circle centered at -2 - -2 with radius 3.
When the function is not defined for all real numbers -; only a subset of the real numbers.
Undefined - because we can'T divide by 0.
The objects within a set.

31. Which quadrant is the upper right hand?
A reflection about the origin.
1/2 times 7/3
I
23 - 29

32. What does scientific notation mean?
87.5%
Relationship cannot be determined (what if x is negative?)
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
A set with no members - denoted by a circle with a diagonal through it.

33. Factor a^2 + 2ab + b^2
All numbers multiples of 1.
(a + b)^2
2sqrt6
7 / 1000

34. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
4096
4725
130pi
The interesection of A and B.

35. Which is greater? 64^5 or 16^8
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
All numbers multiples of 1.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
.0004809 X 10^11

36. What is the slope of a horizontal line?
Yes - like radicals can be added/subtracted.
4725
Move the decimal point to the right x places
0

37. Define a 'monomial'
A chord is a line segment joining two points on a circle.
Angle/360 x 2(pi)r
An expression with just one term (-6x - 2a^2)
72

38. What is the 'domain' of a function?
28. n = 8 - k = 2. n! / k!(n-k)!
A = pi(r^2)
The set of input values for a function.
Divide by 100.

39. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
1.0843 X 10^11
8
1
All numbers multiples of 1.

40. When the 'a' in a parabola is positive....
The set of elements which can be found in either A or B.
C = 2(pi)r
The longest arc between points A and B on a circle'S diameter.
The curve opens upward and the vertex is the minimal point on the graph.

41. 1/6 in percent?
12.5%
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)
3
16.6666%

42. Length of an arc of a circle?
75:11
Angle/360 x 2(pi)r
An expression with just one term (-6x - 2a^2)
The interesection of A and B.

43. 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
130pi
18
1/a^6
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

44. Which is greater? 200x^295 or 10x^294?
Relationship cannot be determined (what if x is negative?)
IV
11 - 13 - 17 - 19
10

45. 10^6 has how many zeroes?
No - only like radicals can be added.
y = (x + 5)/2
2^9 / 2 = 256
6

46. 20<all primes<30
61 - 67
...multiply by 100.
23 - 29
(a - b)^2

47. What does the graph x^2 + y^2 = 64 look like?
(amount of increase/original price) x 100%
A circle centered on the origin with radius 8.
C = (pi)d
5

48. What is the side length of an equilateral triangle with altitude 6?
F(x + c)
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
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...
1.7

49. What is the graph of f(x) shifted downward c units or spaces?
1/(x^y)
F(x) - c
(base*height) / 2
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

50. A number is divisible by 3 if ...
The sum of its digits is divisible by 3.
12.5%
130pi
288 (8 9 4)