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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 is a tangent?
A tangent is a line that only touches one point on the circumference of a circle.
The curve opens upward and the vertex is the minimal point on the graph.
.0004809 X 10^11
F(x-c)

2. What number between 70 & 75 - inclusive - has the greatest number of factors?
The longest arc between points A and B on a circle'S diameter.
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
Infinite.
72

3. x^4 + x^7 =
2 & 3/7
$11 -448
x^(4+7) = x^11
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.

4. 10^6 has how many zeroes?
6
From northeast - counterclockwise. I - II - III - IV
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
Cd

5. Pi is a ratio of what to what?

6. Circumference of a circle?
IV
Diameter(Pi)
Two angles whose sum is 90.
C = (pi)d

7. x^6 / x^3
A subset.
x^(6-3) = x^3
3
II

8. Describe the relationship between the graphs of x^2 and (1/2)x^2
F(x + c)
Two angles whose sum is 180.
Undefined - because we can'T divide by 0.
The second graph is less steep.

9. In a triangle where the two legs are 4 and 3 - what is the value of a line directly intersecting the middle coming from the meeting point of the two legs?
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
1 & 37/132
(a + b)^2
N! / (n-k)!

10. How to find the circumference of a circle which circumscribes a square?
12! / 5!7! = 792
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
23 - 29
3 - -3

11. A number is divisible by 9 if...
3/2 - 5/3
$3 -500 in the 9% and $2 -500 in the 7%.
The sum of digits is divisible by 9.
Even

12. What is the ratio of the sides of an isosceles right triangle?
Pi is the ratio of a circle'S circumference to its diameter.
Part = Percent X Whole
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
1:1:sqrt2

13. 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?
10! / 3!(10-3)! = 120
13
F(x) - c
Sector area = (n/360) X (pi)r^2

14. 25^(1/2) or sqrt. 25 =
5 OR -5
Its negative reciprocal. (-b/a)
288 (8 9 4)
20.5

15. Can you simplify sqrt72?
Ax^2 + bx + c where a -b and c are constants and a /=0
The longest arc between points A and B on a circle'S diameter.
An expression with just one term (-6x - 2a^2)
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

16. What are the integers?
(b + c)
All numbers multiples of 1.
The third side is greater than the difference and less than the sum.
12sqrt2

17. (-1)^3 =
The objects within a set.
Arc length = (n/360) x pi(2r) where n is the number of degrees.
1
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

18. What is the intersection of A and B?
The set of elements found in both A and B.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
61 - 67
The empty set - denoted by a circle with a diagonal through it.

19. Solve the quadratic equation ax^2 + bx + c= 0
1/(x^y)
2
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
F(x) + c

20. 7/8 in percent?
180 degrees
The two xes after factoring.
87.5%
4096

21. How many digits are there between the decimal point and the first even digit in the decimal equivalent of 1/[(2^8)(5^3)]
(n-2) x 180
Ax^2 + bx + c where a -b and c are constants and a /=0
0
3/2 - 5/3

22. 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
Undefined - because we can'T divide by 0.
75:11
x(x - y + 1)

23. To convert a decimal to a percent...
The set of output values for a function.
...multiply by 100.
13
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)

24. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
A 30-60-90 triangle.
The curve opens upward and the vertex is the minimal point on the graph.
3
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

25. (12sqrt15) / (2sqrt5) =
Undefined
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
1
5 OR -5

26. What are 'Supplementary angles?'
Two angles whose sum is 180.
True
2.592 kg
1:sqrt3:2

27. Formula to find a circle'S circumference from its diameter?
IV
The set of elements found in both A and B.
C = (pi)d
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)

28. What is the maximum value for the function g(x) = (-2x^2) -1?
2(pi)r^2 + 2(pi)rh
3 - -3
A set with no members - denoted by a circle with a diagonal through it.
1

29. What is the absolute value function?
y = (x + 5)/2
An expression with just one term (-6x - 2a^2)
G(x) = {x}
1

30. Simplify 9^(1/2) X 4^3 X 2^(-6)?
1
3
53 - 59
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)

31. 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?
9 : 25
41 - 43 - 47
10
1

32. Can the input value of a function have more than one output value (i.e. x: y - y1)?
No - the input value has exactly one output.
The shortest arc between points A and B on a circle'S diameter.
Arc length = (n/360) x pi(2r) where n is the number of degrees.
A subset.

33. 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
18
180
The third side is greater than the difference and less than the sum.
3/2 - 5/3

34. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
F(x-c)
8
The set of elements which can be found in either A or B.
A subset.

35. Which is greater? 64^5 or 16^8
4:5
A central angle is an angle formed by 2 radii.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
12.5%

36. What is a finite set?
The set of input values for a function.
0
A set with a number of elements which can be counted.
55%

37. a^2 - 2ab + b^2
From northeast - counterclockwise. I - II - III - IV
F(x) - c
2sqrt6
(a - b)^2

38. (x^2)^4
Yes - like radicals can be added/subtracted.
An infinite set.
23 - 29
x^(2(4)) =x^8 = (x^4)^2

39. Which quadrant is the upper right hand?
The curve opens downward and the vertex is the maximum point on the graph.
I
The empty set - denoted by a circle with a diagonal through it.
3/2 - 5/3

40. How to determine percent decrease?
37.5%
A set with no members - denoted by a circle with a diagonal through it.
Yes - like radicals can be added/subtracted.
(amount of decrease/original price) x 100%

41. A number is divisible by 6 if...
Part = Percent X Whole
Its divisible by 2 and by 3.
180 degrees
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

42. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
12! / 5!7! = 792
x^(2(4)) =x^8 = (x^4)^2
y = 2x^2 - 3
3sqrt4

43. Simplify (a^2 + b)^2 - (a^2 - b)^2
4a^2(b)
The union of A and B.
90 degrees
1

44. What is the formula for compounded interest?
2 & 3/7
23 - 29
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.
12.5%

45. 5x^2 - 35x -55 = 0
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
(a + b)^2
27^(-4)
20.5

46. A number is divisible by 3 if ...
A = pi(r^2)
The sum of its digits is divisible by 3.
Members or elements
The union of A and B.

47. Evaluate 3& 2/7 / 1/3
III
1
130pi
9 & 6/7

48. How to determine percent increase?
90 degrees
The longest arc between points A and B on a circle'S diameter.
(amount of increase/original price) x 100%
2 & 3/7

49. Area of a triangle?
(base*height) / 2
All numbers multiples of 1.
A reflection about the axis.
The point of intersection of the systems.

50. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
90
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
A circle centered at -2 - -2 with radius 3.
4:5