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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. 5/8 in percent?
3/2 - 5/3
...multiply by 100.
62.5%
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)

2. What is the maximum value for the function g(x) = (-2x^2) -1?
72
Ax^2 + bx + c where a -b and c are constants and a /=0
1
A chord is a line segment joining two points on a circle.

3. 5x^2 - 35x -55 = 0
(a - b)(a + b)
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
4a^2(b)

4. What does scientific notation mean?
71 - 73 - 79
72
75:11
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

5. 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?
413.03 / 10^4 (move the decimal point 4 places to the left)
(base*height) / 2
10! / 3!(10-3)! = 120
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.

6. What is the set of elements found in both A and B?
Two equal sides and two equal angles.
The interesection of A and B.
3
1

7. What is a tangent?
A subset.
A tangent is a line that only touches one point on the circumference of a circle.
F(x + c)
I

8. What is the absolute value function?
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
18
3/2 - 5/3
G(x) = {x}

9. How to determine percent increase?
(amount of increase/original price) x 100%
y = 2x^2 - 3
The steeper the slope.
41 - 43 - 47

10. A number is divisible by 9 if...
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
The sum of digits is divisible by 9.
The steeper the slope.
(n-2) x 180

11. x^(-y)=
1/2 times 7/3
A set with a number of elements which can be counted.
The set of elements found in both A and B.
1/(x^y)

12. Area of a triangle?
13pi / 2
1 & 37/132
0
(base*height) / 2

13. sqrt 2(sqrt 6)=
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
Sqrt 12
Angle/360 x 2(pi)r
61 - 67

14. The ratio of the areas of two similar polygons is ...
... the square of the ratios of the corresponding sides.
23 - 29
10! / (10-3)! = 720
IV

15. 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?
An isosceles right triangle.
The curve opens downward and the vertex is the maximum point on the graph.
The overlapping sections.
500

16. To convert a percent to a fraction....
13pi / 2
x^(4+7) = x^11
Divide by 100.
The curve opens downward and the vertex is the maximum point on the graph.

17. Convert 0.7% to a fraction.
441000 = 1 10 10 10 21 * 21
7 / 1000
C = 2(pi)r
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)

18. Circumference of a circle?
Diameter(Pi)
288 (8 9 4)
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
130pi

19. 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)
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.
4725
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...

20. What are the roots of the quadrinomial x^2 + 2x + 1?
The two xes after factoring.
N! / (n-k)!
1
Undefined - because we can'T divide by 0.

21. a^0 =
16.6666%
Lies opposite the greater angle
N! / (k!)(n-k)!
1

22. If r - t - s & u are distinct - consecutive prime numbers - less than 31 - which of the following could be an average of them (4 - 4.25 - 6 - 9 - 24 - 22 - 24)
4.25 - 6 - 22
70
C = (pi)d
The third side is greater than the difference and less than the sum.

23. A brick with dimensions 10. 15 and 25 weighs 1.5 kg. A second brick (same density) has dimensions 12 - 18 - and 30. What is the weight of the second brick?
The empty set - denoted by a circle with a diagonal through it.
2.592 kg
Yes. [i.e. f(x) = x^2 - 1
A reflection about the origin.

24. What are the smallest three prime numbers greater than 65?
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
67 - 71 - 73
(amount of increase/original price) x 100%
The set of input values for a function.

25. Volume for a cylinder?
Indeterminable.
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)
Area of the base X height = (pi)hr^2
10! / (10-3)! = 720

26. Formula to find a circle'S circumference from its diameter?
10! / 3!(10-3)! = 120
2.592 kg
C = (pi)d
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

27. If a=-1 and b=3 - what is the value of (4(a^3)(b^2) - 12(a^2)(b^5)) / (16(a^3)(b^2))?
20.5
... the square of the ratios of the corresponding sides.
1/(x^y)
83.333%

28. When the 'a' in the parabola is negative...
8
The curve opens downward and the vertex is the maximum point on the graph.
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
The curve opens upward and the vertex is the minimal point on the graph.

29. 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?
(p + q)/5
The curve opens upward and the vertex is the minimal point on the graph.
Yes. [i.e. f(x) = x^2 - 1
48

30. Legs 5 - 12. Hypotenuse?
13
3sqrt4
3
All numbers multiples of 1.

31. What is the 'Range' of a series of numbers?
4a^2(b)
Two angles whose sum is 180.
The greatest value minus the smallest.
$3 -500 in the 9% and $2 -500 in the 7%.

32. 7/8 in percent?
9 : 25
87.5%
Its negative reciprocal. (-b/a)
10! / (10-3)! = 720

33. 60 < all primes <70
Undefined - because we can'T divide by 0.
The steeper the slope.
61 - 67
1:1:sqrt2

34. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
1
Part = Percent X Whole
N! / (n-k)!
.0004809 X 10^11

35. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
72
(p + q)/5
8
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

36. Find the surface area of a cylinder with radius 3 and height 12.
90pi
An infinite set.
(a - b)(a + b)
A set with no members - denoted by a circle with a diagonal through it.

37. Evaluate 4/11 + 11/12
8
Two angles whose sum is 180.
A subset.
1 & 37/132

38. Which quandrant is the lower right hand?
G(x) = {x}
Infinite.
IV
70

39. 40 < all primes<50
41 - 43 - 47
2
Diameter(Pi)
1

40. Order of quadrants:
A = pi(r^2)
12.5%
Its last two digits are divisible by 4.
From northeast - counterclockwise. I - II - III - IV

41. Reduce: 4.8 : 0.8 : 1.6
III
Lies opposite the greater angle
13
6 : 1 : 2

42. (-1)^3 =
G(x) = {x}
.0004809 X 10^11
y = (x + 5)/2
1

43. What is the formula for computing simple interest?
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)
90pi
A = I (1 + rt)
x^(4+7) = x^11

44. How many digits are there between the decimal point and the first even digit in the decimal equivalent of 1/[(2^8)(5^3)]
10
Triangles with same measure and same side lengths.
0
N! / (n-k)!

45. In a triangle inscribed inside a circle - where the diameter is one side of the triangle - which angle is largest?
A circle centered at -2 - -2 with radius 3.
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
90 degrees

46. How many sides does a hexagon have?
6
The interesection of A and B.
(n-2) x 180
An expression with just one term (-6x - 2a^2)

47. Can you simplify sqrt72?
Infinite.
N! / (n-k)!
2.592 kg
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

48. Evaluate (4^3)^2
13
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
4096
(a + b)^2

49. What are the real numbers?
Its divisible by 2 and by 3.
413.03 / 10^4 (move the decimal point 4 places to the left)
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)
Even

50. Pi is a ratio of what to what?