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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. Factor x^2 - xy + x.
5
x(x - y + 1)
Cd
31 - 37

2. 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?
Even
A = pi(r^2)
9 : 25
90 degrees

3. Suppose that the graph of f(x) is the result of sliding the graph of y=2x^2 down 3 units of spaces. What is the new equation?
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)
y = 2x^2 - 3
Yes - like radicals can be added/subtracted.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16

4. Which is greater? 200x^295 or 10x^294?
A grouping of the members within a set based on a shared characteristic.
The interesection of A and B.
7 / 1000
Relationship cannot be determined (what if x is negative?)

5. Describe the relationship between the graphs of x^2 and (1/2)x^2
The second graph is less steep.
The empty set - denoted by a circle with a diagonal through it.
All numbers multiples of 1.
Diameter(Pi)

6. To convert a percent to a fraction....
23 - 29
(a - b)(a + b)
Divide by 100.
An angle which is supplementary to an interior angle.

7. Which quadrant is the lower left hand?
III
.0004809 X 10^11
Angle/360 x (pi)r^2
70

8. 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)]?
1/(x^y)
True
All numbers multiples of 1.
Two angles whose sum is 180.

9. 1/8 in percent?
12.5%
Factors are few - multiples are many.
The longest arc between points A and B on a circle'S diameter.
71 - 73 - 79

10. Legs 5 - 12. Hypotenuse?
13
A = I (1 + rt)
130pi
The steeper the slope.

11. What is the 'union' of A and B?
Two angles whose sum is 90.
The set of elements which can be found in either A or B.
An expression with just one term (-6x - 2a^2)
67 - 71 - 73

12. a^2 + 2ab + b^2
(a + b)^2
441000 = 1 10 10 10 21 * 21
75:11
All numbers multiples of 1.

13. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
2^9 / 2 = 256
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
x(x - y + 1)
A = I (1 + rt)

14. sqrt 2(sqrt 6)=
Relationship cannot be determined (what if x is negative?)
The union of A and B.
Sqrt 12
90

15. (a^-1)/a^5
1
Diameter(Pi)
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)
1/a^6

16. When the 'a' in a parabola is positive....
An isosceles right triangle.
C = (pi)d
Cd
The curve opens upward and the vertex is the minimal point on the graph.

17. 0^0
90 degrees
Its divisible by 2 and by 3.
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.
Undefined

18. 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?
1
10! / 3!(10-3)! = 120
130pi
Undefined

19. How to find the circumference of a circle which circumscribes a square?
10
$3 -500 in the 9% and $2 -500 in the 7%.
Circumference = Diameter(pi). Use pythagorean theorem to find the diagonal of the square (the diameter).
G(x) = {x}

20. What is an exterior angle?
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)
87.5%
Its last two digits are divisible by 4.
An angle which is supplementary to an interior angle.

21. What is the set of elements found in both A and B?
The interesection of A and B.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
413.03 / 10^4 (move the decimal point 4 places to the left)
5 OR -5

22. 1/6 in percent?
16.6666%
2 & 3/7
A = pi(r^2)
20.5

23. Can the input value of a function have more than one output value (i.e. x: y - y1)?
An isosceles right triangle.
No - the input value has exactly one output.
C = (pi)d
F(x-c)

24. x^4 + x^7 =
x^(4+7) = x^11
A subset.
Relationship cannot be determined (what if x is negative?)
0

25. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
500
II
F(x + c)
4725

26. The perimeter of a square is 48 inches. The length of its diagonal is:
12sqrt2
4096
Pi is the ratio of a circle'S circumference to its diameter.
Move the decimal point to the right x places

27. Circumference of a circle?
A set with no members - denoted by a circle with a diagonal through it.
Diameter(Pi)
55%
F(x) + c

28. x^(-y)=
9 & 6/7
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
1/(x^y)
III

29. What is the 'Range' of a series of numbers?
Members or elements
4a^2(b)
0
The greatest value minus the smallest.

30. 6w^2 - w - 15 = 0
3/2 - 5/3
90pi
Members or elements
A set with no members - denoted by a circle with a diagonal through it.

31. What is it called when a point is reflected to the quadrant opposite it (i.e. I to III or II to IV)?
No - only like radicals can be added.
x^(4+7) = x^11
(a - b)(a + b)
A reflection about the origin.

32. 70 < all primes< 80
Infinite.
y = (x + 5)/2
71 - 73 - 79
Angle/360 x 2(pi)r

33. Simplify (a^2 + b)^2 - (a^2 - b)^2
IV
4a^2(b)
3sqrt4
C = (pi)d

34. Formula to find a circle'S circumference from its diameter?
(b + c)
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
10! / 3!(10-3)! = 120
C = (pi)d

35. Which quadrant is the upper right hand?
130pi
1/2 times 7/3
I
Divide by 100.

36. What is a central angle?
A central angle is an angle formed by 2 radii.
A reflection about the origin.
Triangles with same measure and same side lengths.
Yes - like radicals can be added/subtracted.

37. What is a finite set?
The sum of digits is divisible by 9.
12.5%
A set with a number of elements which can be counted.
The curve opens upward and the vertex is the minimal point on the graph.

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?
72
10! / (10-3)! = 720
87.5%
2(pi)r^2 + 2(pi)rh

39. What is an arc of a circle?
1 & 37/132
x^(4+7) = x^11
An arc is a portion of a circumference of a circle.
The empty set - denoted by a circle with a diagonal through it.

40. Which is greater? 64^5 or 16^8
A circle centered on the origin with radius 8.
A circle centered at -2 - -2 with radius 3.
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
62.5%

41. 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?
500
A circle centered at -2 - -2 with radius 3.
31 - 37
The point of intersection of the systems.

42. What is the common monomial factor in the expression 4(c^3)d - (c^2)(d^2) + 2cd?
Move the decimal point to the right x places
Cd
288 (8 9 4)
3

43. What is the ratio of the sides of an isosceles right triangle?
1/2 times 7/3
2.592 kg
Infinite.
1:1:sqrt2

44. Can the output value of a function have more than one input value?
(n-2) x 180
Undefined - because we can'T divide by 0.
Its negative reciprocal. (-b/a)
Yes. [i.e. f(x) = x^2 - 1

45. What are the smallest three prime numbers greater than 65?
Angle/360 x (pi)r^2
87.5%
A circle centered at -2 - -2 with radius 3.
67 - 71 - 73

46. Is 0 even or odd?
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...
13pi / 2
C = 2(pi)r
Even

47. Evaluate and write as a mixed number: 2/7 - 3/21 + 2 & 4/14
55%
2 & 3/7
An expression with just one term (-6x - 2a^2)
F(x + c)

48. What is the 'Solution' for a set of inequalities.
Yes. [i.e. f(x) = x^2 - 1
Cd
The overlapping sections.
Part = Percent X Whole

49. 1/2 divided by 3/7 is the same as
C = (pi)d
The set of elements found in both A and B.
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
1/2 times 7/3

50. The ratio of the areas of two similar polygons is ...
... the square of the ratios of the corresponding sides.
3
x^(4+7) = x^11
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.