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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 the 'Restricted domain of a function'?
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
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.
0

2. What is the slope of a horizontal line?
3 - -3
x^(6-3) = x^3
The set of elements found in both A and B.
0

3. 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
A central angle is an angle formed by 2 radii.
18
48
1.7

4. (a^-1)/a^5
Part = Percent X Whole
The interesection of A and B.
1/a^6
130pi

5. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
Cd
The steeper the slope.
IV
70

6. 3/8 in percent?
53 - 59
37.5%
Sqrt 12
A = I (1 + rt)

7. 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)?
Divide by 100.
y = (x + 5)/2
Area of the base X height = (pi)hr^2
4:5

8. Which quadrant is the upper left hand?
An isosceles right triangle.
A reflection about the axis.
No - only like radicals can be added.
II

9. Convert 0.7% to a fraction.
x^(2(4)) =x^8 = (x^4)^2
72
10! / (10-3)! = 720
7 / 1000

10. When the 'a' in a parabola is positive....
1
Lies opposite the greater angle
G(x) = {x}
The curve opens upward and the vertex is the minimal point on the graph.

11. Which is greater? 27^(-4) or 9^(-8)
A set with no members - denoted by a circle with a diagonal through it.
27^(-4)
Ax^2 + bx + c where a -b and c are constants and a /=0
75:11

12. Which is greater? 64^5 or 16^8
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
1/2 times 7/3
413.03 / 10^4 (move the decimal point 4 places to the left)
A set with no members - denoted by a circle with a diagonal through it.

13. a^2 - b^2 =
Undefined - because we can'T divide by 0.
18
1/(x^y)
(a - b)(a + b)

14. What are the real numbers?
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)
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
Factors are few - multiples are many.
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

15. (-1)^2 =
1
x^(2(4)) =x^8 = (x^4)^2
2sqrt6
5 OR -5

16. Simplify (a^2 + b)^2 - (a^2 - b)^2
4a^2(b)
The curve opens downward and the vertex is the maximum point on the graph.
1.0843 X 10^11
C = 2(pi)r

17. Which quadrant is the lower left hand?
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)
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
III
18

18. 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?
Ax^2 + bx + c where a -b and c are constants and a /=0
No - the input value has exactly one output.
1.7
500

19. Surface area for a cylinder?
288 (8 9 4)
2(pi)r^2 + 2(pi)rh
67 - 71 - 73
Lies opposite the greater angle

20. Number of degrees in a triangle
16.6666%
IV
Angle/360 x (pi)r^2
180

21. 60 < all primes <70
61 - 67
2^9 / 2 = 256
... the square of the ratios of the corresponding sides.
Undefined - because we can'T divide by 0.

22. Describe the relationship between 3x^2 and 3(x - 1)^2
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
A central angle is an angle formed by 2 radii.
An arc is a portion of a circumference of a circle.
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

23. What does scientific notation mean?
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
180 degrees
A circle centered on the origin with radius 8.
1

24. There are 10 finalists for the school spelling bee. A first - second - and third place trophy will be awarded. In how many ways can the judges award the 3 prizes?
3sqrt4
10! / (10-3)! = 720
C = 2(pi)r
Pi is the ratio of a circle'S circumference to its diameter.

25. Simplify the expression [(b^2 - c^2) / (b - c)]
(b + c)
23 - 29
90pi
Pi is the ratio of a circle'S circumference to its diameter.

26. (x^2)^4
(p + q)/5
0
Its last two digits are divisible by 4.
x^(2(4)) =x^8 = (x^4)^2

27. 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?
Relationship cannot be determined (what if x is negative?)
75:11
Its last two digits are divisible by 4.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

28. What is the set of elements which can be found in either A or B?
No - only like radicals can be added.
31 - 37
The union of A and B.
x^(6-3) = x^3

29. What are 'Supplementary angles?'
62.5%
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Two angles whose sum is 180.
The interesection of A and B.

30. What is the empty set?
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
67 - 71 - 73
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)
A set with no members - denoted by a circle with a diagonal through it.

31. In similar hexagons - the ratio of the areas is 16:25. What is the ratio of their corresponding sides?
1 & 37/132
Area of the base X height = (pi)hr^2
4:5
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.

32. 6w^2 - w - 15 = 0
The sum of its digits is divisible by 3.
2^9 / 2 = 256
A reflection about the origin.
3/2 - 5/3

33. What is an exterior angle?
Two equal sides and two equal angles.
An angle which is supplementary to an interior angle.
x^(6-3) = x^3
11 - 13 - 17 - 19

34. A number is divisible by 4 is...
Its negative reciprocal. (-b/a)
True
Its last two digits are divisible by 4.
The overlapping sections.

35. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
An isosceles right triangle.
2 & 3/7
55%
90

36. Formula to find a circle'S circumference from its radius?
C = 2(pi)r
2
Lies opposite the greater angle
Its last two digits are divisible by 4.

37. The perimeter of a square is 48 inches. The length of its diagonal is:
x^(6-3) = x^3
x(x - y + 1)
12sqrt2
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)

38. What is a chord of a circle?
The union of A and B.
A chord is a line segment joining two points on a circle.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
.0004809 X 10^11

39. Legs: 3 - 4. Hypotenuse?
G(x) = {x}
Angle/360 x (pi)r^2
5
67 - 71 - 73

40. For similar triangles - the ratio of their corresponding sides is 2:3. What is the ratio of their areas?
1 & 37/132
Infinite.
1/2 times 7/3
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.

41. a^0 =
The union of A and B.
A = pi(r^2)
Angle/360 x 2(pi)r
1

42. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
12! / 5!7! = 792
13pi / 2
3 - -3
The empty set - denoted by a circle with a diagonal through it.

43. Circumference of a circle?
72
Its divisible by 2 and by 3.
Diameter(Pi)
6 : 1 : 2

44. If an inequality is multiplied or divided by a negative number....
An isosceles right triangle.
Sqrt 12
61 - 67
The direction of the inequality is reversed.

45. A cylinder has a surface area of 22pi. If the cylinder has a height of 10 - what is the radius?
x^(2(4)) =x^8 = (x^4)^2
1/(x^y)
Yes. [i.e. f(x) = x^2 - 1
1

46. Reduce: 4.8 : 0.8 : 1.6
1:sqrt3:2
The set of elements which can be found in either A or B.
6 : 1 : 2
72

47. Evaluate 4/11 + 11/12
3
The longest arc between points A and B on a circle'S diameter.
23 - 29
1 & 37/132

48. What transformation occurs if point C is reflected over the x-axis and then the y-axis?
C = 2(pi)r
$11 -448
A reflection about the axis.
11 - 13 - 17 - 19

49. Max and Min lengths for a side of a triangle?
The third side is greater than the difference and less than the sum.
500
(amount of increase/original price) x 100%
10! / 3!(10-3)! = 120

50. What are congruent triangles?
1
441000 = 1 10 10 10 21 * 21
Triangles with same measure and same side lengths.
53 - 59