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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. 5x^2 - 35x -55 = 0
Angle/360 x 2(pi)r
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
12.5%
The curve opens downward and the vertex is the maximum point on the graph.

2. What is the graph of f(x) shifted downward c units or spaces?
Undefined
1:1:sqrt2
5
F(x) - c

3. 10^6 has how many zeroes?
The greatest value minus the smallest.
F(x) + c
6
The objects within a set.

4. Circumference of a circle?
The third side is greater than the difference and less than the sum.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
Diameter(Pi)
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)

5. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
1
No - the input value has exactly one output.
180
The longest arc between points A and B on a circle'S diameter.

6. Max and Min lengths for a side of a triangle?
3/2 - 5/3
55%
The third side is greater than the difference and less than the sum.
12sqrt2

7. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
N! / (k!)(n-k)!
(b + c)
87.5%
$11 -448

8. Which is greater? 200x^295 or 10x^294?
Relationship cannot be determined (what if x is negative?)
... the square of the ratios of the corresponding sides.
The direction of the inequality is reversed.
G(x) = {x}

9. How many sides does a hexagon have?
A 30-60-90 triangle.
6
The direction of the inequality is reversed.
4725

10. How to find the circumference of a circle which circumscribes a square?
G(x) = {x}
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
1 & 37/132
The steeper the slope.

11. 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.
The direction of the inequality is reversed.
90 degrees
$3 -500 in the 9% and $2 -500 in the 7%.
72

12. 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
4.25 - 6 - 22
37.5%
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

13. A number is divisible by 3 if ...
C = (pi)d
The sum of its digits is divisible by 3.
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
The set of output values for a function.

14. 20<all primes<30
x^(6-3) = x^3
1
23 - 29
87.5%

15. (x^2)^4
A circle centered at -2 - -2 with radius 3.
12sqrt2
2.592 kg
x^(2(4)) =x^8 = (x^4)^2

16. a^2 - 2ab + b^2
(a - b)^2
x^(6-3) = x^3
2 & 3/7
A central angle is an angle formed by 2 radii.

17. 50 < all primes< 60
1:sqrt3:2
F(x) - c
53 - 59
Part = Percent X Whole

18. Can you simplify sqrt72?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
(amount of increase/original price) x 100%
The set of output values for a function.
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

19. How to determine percent decrease?
(amount of decrease/original price) x 100%
52
12.5%
The shortest arc between points A and B on a circle'S diameter.

20. 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.
3sqrt4
y = (x + 5)/2
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...

21. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
1:sqrt3:2
Area of the base X height = (pi)hr^2
70

22. 3/8 in percent?
37.5%
All numbers multiples of 1.
A reflection about the axis.
13pi / 2

23. a^2 - b^2
1
(a - b)(a + b)
90 degrees
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)

24. Simplify the expression [(b^2 - c^2) / (b - c)]
Sector area = (n/360) X (pi)r^2
12.5%
(b + c)
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.

25. Evaluate (4^3)^2
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
4096
From northeast - counterclockwise. I - II - III - IV
A reflection about the origin.

26. a^2 - b^2 =
4a^2(b)
(a - b)(a + b)
1
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15

27. The ratio of the areas of two similar polygons is ...
(amount of decrease/original price) x 100%
C = 2(pi)r
The second graph is less steep.
... the square of the ratios of the corresponding sides.

28. What is a chord of a circle?
52
13
A chord is a line segment joining two points on a circle.
11 - 13 - 17 - 19

29. Formula to calculate arc length?
Arc length = (n/360) x pi(2r) where n is the number of degrees.
1
4:5
1 & 37/132

30. 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?
A set with no members - denoted by a circle with a diagonal through it.
y = (x + 5)/2
A set with a number of elements which can be counted.
10! / 3!(10-3)! = 120

31. Legs: 3 - 4. Hypotenuse?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
Pi is the ratio of a circle'S circumference to its diameter.
5
N! / (n-k)!

32. To convert a decimal to a percent...
(a - b)(a + b)
1:1:sqrt2
5 OR -5
...multiply by 100.

33. What is the graph of f(x) shifted upward c units or spaces?
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
Its last two digits are divisible by 4.
75:11
F(x) + c

34. What are complementary angles?
Two angles whose sum is 90.
$3 -500 in the 9% and $2 -500 in the 7%.
10! / (10-3)! = 720
2.592 kg

35. 200 <_ x <_ 300. How many values of x are divisible by 5 & 8?
72
3
12.5%
An angle which is supplementary to an interior angle.

36. x^6 / x^3
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
x^(6-3) = x^3
(a + b)^2

37. What is the 'union' of A and B?
The set of elements which can be found in either A or B.
A reflection about the axis.
Its last two digits are divisible by 4.
An angle which is supplementary to an interior angle.

38. 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?
Area of the base X height = (pi)hr^2
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)
10! / (10-3)! = 720
Part = Percent X Whole

39. 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
Its last two digits are divisible by 4.
413.03 / 10^4 (move the decimal point 4 places to the left)
(a - b)(a + b)

40. 60 < all primes <70
61 - 67
(base*height) / 2
4a^2(b)
... the square of the ratios of the corresponding sides.

41. Legs 6 - 8. Hypotenuse?
.0004809 X 10^11
(b + c)
10! / (10-3)! = 720
10

42. What percent of 40 is 22?
3
The set of input values for a function.
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
55%

43. What is the slope of a horizontal line?
0
2
67 - 71 - 73
2(pi)r^2 + 2(pi)rh

44. What is a subset?
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
A grouping of the members within a set based on a shared characteristic.
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...

45. A company places a 6-symbol code on each product. The code consists of the letter T - followed by 3 numerical digits - and then 2 consonants (Y is a conson). How many codes are possible?
True
2
441000 = 1 10 10 10 21 * 21
1.7

46. What is an exterior angle?
An angle which is supplementary to an interior angle.
(a - b)(a + b)
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
The sum of digits is divisible by 9.

47. What is the 'domain' of a function?
3 - -3
The set of input values for a function.
90 degrees
6

48. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
4725
71 - 73 - 79
12! / 5!7! = 792
90 degrees

49. 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.
500
75:11
Arc length = (n/360) x pi(2r) where n is the number of degrees.

50. P and r are factors of 100. What is greater - pr or 100?
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
7 / 1000
The two xes after factoring.
Indeterminable.