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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. 2sqrt4 + sqrt4 =
0
(a - b)^2
3sqrt4
The third side is greater than the difference and less than the sum.

2. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
Angle/360 x (pi)r^2
A set with no members - denoted by a circle with a diagonal through it.
3sqrt4
3

3. 5/6 in percent?
F(x + c)
x(x - y + 1)
83.333%
13

4. How to find the area of a sector?
4725
Angle/360 x (pi)r^2
The objects within a set.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

5. What is the coefficient of the x^2 term in the product of (x + 1)(x + 2)(x -1)?
(a - b)(a + b)
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
3/2 - 5/3
2

6. x^(-y)=
1/(x^y)
x(x - y + 1)
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
The curve opens upward and the vertex is the minimal point on the graph.

7. To convert a percent to a fraction....
1:sqrt3:2
Divide by 100.
8
The set of elements found in both A and B.

8. What is the maximum value for the function g(x) = (-2x^2) -1?
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
N! / (n-k)!
7 / 1000
1

9. 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)?
y = (x + 5)/2
x= (1.2)(.8)lw
(base*height) / 2
Sector area = (n/360) X (pi)r^2

10. Which quandrant is the lower right hand?
The union of A and B.
IV
41 - 43 - 47
1.7

11. What is the set of elements found in both A and B?
A circle centered at -2 - -2 with radius 3.
The interesection of A and B.
Undefined - because we can'T divide by 0.
18

12. 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?
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
5 OR -5
75:11
A central angle is an angle formed by 2 radii.

13. 5/8 in percent?
62.5%
... the square of the ratios of the corresponding sides.
...multiply by 100.
55%

14. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
An isosceles right triangle.
x^(2(4)) =x^8 = (x^4)^2
4725
A subset.

15. Formula to find a circle'S circumference from its diameter?
9 : 25
4a^2(b)
C = (pi)d
Two angles whose sum is 180.

16. What number between 70 & 75 - inclusive - has the greatest number of factors?
72
48
The steeper the slope.
The empty set - denoted by a circle with a diagonal through it.

17. What is the 'Restricted domain of a function'?
31 - 37
Divide by 100.
When the function is not defined for all real numbers -; only a subset of the real numbers.
The second graph is less steep.

18. Simplify the expression [(b^2 - c^2) / (b - c)]
70
N! / (n-k)!
180
(b + c)

19. Can you simplify sqrt72?
When the function is not defined for all real numbers -; only a subset of the real numbers.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
The sum of digits is divisible by 9.
A reflection about the axis.

20. Simplify 4sqrt21 X 5sqrt2 / 10sqrt7
1.7
2sqrt6
Move the decimal point to the right x places
3 - -3

21. What is an exterior angle?
12.5%
An angle which is supplementary to an interior angle.
No - the input value has exactly one output.
F(x + c)

22. a^2 + 2ab + b^2
10! / 3!(10-3)! = 120
(a + b)^2
II
87.5%

23. 70 < all primes< 80
71 - 73 - 79
No - only like radicals can be added.
The sum of its digits is divisible by 3.
The point of intersection of the systems.

24. x^4 + x^7 =
A central angle is an angle formed by 2 radii.
27^(-4)
441000 = 1 10 10 10 21 * 21
x^(4+7) = x^11

25. Reduce: 4.8 : 0.8 : 1.6
Undefined - because we can'T divide by 0.
$3 -500 in the 9% and $2 -500 in the 7%.
6 : 1 : 2
All numbers multiples of 1.

26. What is a subset?
(b + c)
A grouping of the members within a set based on a shared characteristic.
The sum of digits is divisible by 9.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

27. 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?
441000 = 1 10 10 10 21 * 21
The third side is greater than the difference and less than the sum.
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
9 : 25

28. What is an arc of a circle?
II
An arc is a portion of a circumference of a circle.
67 - 71 - 73
Members or elements

29. What is the set of elements which can be found in either A or B?
The shortest arc between points A and B on a circle'S diameter.
(a - b)(a + b)
The union of A and B.
27^(-4)

30. Order of quadrants:
A reflection about the axis.
II
From northeast - counterclockwise. I - II - III - IV
The direction of the inequality is reversed.

31. What are 'Supplementary angles?'
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
Two angles whose sum is 180.
2 & 3/7
2

32. 5 bakeries sell an average of 300 muffins per bakery per day. If 2 stop making muffins but the total muffins sold stays the same - what is the average of muffins per bakery sold among the remaining?
N! / (k!)(n-k)!
500
12sqrt2
7 / 1000

33. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
28. n = 8 - k = 2. n! / k!(n-k)!
2 & 3/7
71 - 73 - 79
12! / 5!7! = 792

34. Length of an arc of a circle?
x^(4+7) = x^11
Angle/360 x 2(pi)r
83.333%
1.7

35. 10^6 has how many zeroes?
6
The set of elements which can be found in either A or B.
x^(4+7) = x^11
No - the input value has exactly one output.

36. Surface area for a cylinder?
II
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.
Its negative reciprocal. (-b/a)
2(pi)r^2 + 2(pi)rh

37. What is the 'Solution' for a system of linear equations?
1
II
The point of intersection of the systems.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

38. What is the 'Solution' for a set of inequalities.
The overlapping sections.
130pi
A reflection about the origin.
Its last two digits are divisible by 4.

39. 8.84 / 5.2
28. n = 8 - k = 2. n! / k!(n-k)!
An expression with just one term (-6x - 2a^2)
True
1.7

40. What is the ratio of the sides of an isosceles right triangle?
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)
1:1:sqrt2
A = I (1 + rt)
Part = Percent X Whole

41. What is the percent formula?
1
Area of the base X height = (pi)hr^2
55%
Part = Percent X Whole

42. What does the graph x^2 + y^2 = 64 look like?
A circle centered on the origin with radius 8.
The empty set - denoted by a circle with a diagonal through it.
(base*height) / 2
G(x) = {x}

43. Solve the quadratic equation ax^2 + bx + c= 0
10! / (10-3)! = 720
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
3

44. In a regular polygon with n sides - the formula for the sum of interior angles
18
3 - -3
(n-2) x 180
13pi / 2

45. If the two sides of a triangle are unequal then the longer side...
Lies opposite the greater angle
The set of output values for a function.
2 & 3/7
1

46. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
The objects within a set.
2 & 3/7
The direction of the inequality is reversed.
The sum of its digits is divisible by 3.

47. T or F? Given d -e &f =/ 0 - [(d^3)e(f^5)] / 2d(e^3) / [3(d^2)(e^3)(f^7)] / [6(e^5)(f^2)]?
Lies opposite the greater angle
The set of input values for a function.
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...
True

48. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
An angle which is supplementary to an interior angle.
90
When the function is not defined for all real numbers -; only a subset of the real numbers.
.0004809 X 10^11

49. 0^0
48
87.5%
Undefined
The curve opens downward and the vertex is the maximum point on the graph.

50. Simplify the expression (p^2 - q^2)/ -5(q - p)
The greatest value minus the smallest.
(p + q)/5
Its last two digits are divisible by 4.
10! / 3!(10-3)! = 120