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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. For similar triangles - the ratio of their corresponding sides is 2:3. What is the ratio of their areas?
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.
4.25 - 6 - 22
0
G(x) = {x}

2. What does the graph x^2 + y^2 = 64 look like?
Two angles whose sum is 90.
F(x + c)
F(x-c)
A circle centered on the origin with radius 8.

3. What is the set of elements found in both A and B?
4a^2(b)
The interesection of A and B.
75:11
90 degrees

4. The slope of a line perpendicular to (a/b)?
61 - 67
1
Its negative reciprocal. (-b/a)
1/a^6

5. 50 < all primes< 60
... the square of the ratios of the corresponding sides.
67 - 71 - 73
53 - 59
Its negative reciprocal. (-b/a)

6. What are the integers?
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
41 - 43 - 47
All numbers multiples of 1.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3

7. P and r are factors of 100. What is greater - pr or 100?
A 30-60-90 triangle.
2(pi)r^2 + 2(pi)rh
16.6666%
Indeterminable.

8. If 4500 is invested at a simple interest rate of 6% - what is the value of the investment after 10 months?
4725
1
Two angles whose sum is 180.
52

9. To convert a percent to a fraction....
The shortest arc between points A and B on a circle'S diameter.
Sector area = (n/360) X (pi)r^2
Divide by 100.
...multiply by 100.

10. How to find the diagonal of a rectangular solid?
II
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).
A grouping of the members within a set based on a shared characteristic.
13

11. Can you subtract 3sqrt4 from sqrt4?
A = I (1 + rt)
1
Yes - like radicals can be added/subtracted.
The longest arc between points A and B on a circle'S diameter.

12. What are the members or elements of a set?
6
0
y = (x + 5)/2
The objects within a set.

13. 10<all primes<20
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)
441000 = 1 10 10 10 21 * 21
The steeper the slope.
11 - 13 - 17 - 19

14. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
6
9 : 25
(6 x 2)(sqrt3 x sqrt5) = 12sqrt15
2^9 / 2 = 256

15. a^2 + 2ab + b^2
1
(a + b)^2
6
61 - 67

16. How to determine percent decrease?
1/(x^y)
(amount of decrease/original price) x 100%
Yes - like radicals can be added/subtracted.
(a - b)^2

17. What is the ratio of the sides of an isosceles right triangle?
A central angle is an angle formed by 2 radii.
1:1:sqrt2
0
The empty set - denoted by a circle with a diagonal through it.

18. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
An algebraic expression is a combination of one of more terms. Terms in an expression are separated by either addition or subtraction signs. (3xy - 4ab - -5cd - x^2 + x - 1)
$11 -448
288 (8 9 4)
III

19. A cylinder has surface area 22pi. If the cylinder has a height of 10 - what is its radius?
1
52
A grouping of the members within a set based on a shared characteristic.
8

20. Write 10 -843 X 10^7 in scientific notation
1.0843 X 10^11
1
The interesection of A and B.
I

21. What is the slope of a vertical line?

22. 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?
III
x^(4+7) = x^11
y = 2x^2 - 3
90pi

23. sqrt 2(sqrt 6)=
27^(-4)
Sqrt 12
(b + c)
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.

24. 5/6 in percent?
The set of elements which can be found in either A or B.
83.333%
Two angles whose sum is 180.
(b + c)

25. What is a subset?
A grouping of the members within a set based on a shared characteristic.
Two equal sides and two equal angles.
A set with no members - denoted by a circle with a diagonal through it.
Its last two digits are divisible by 4.

26. (a^-1)/a^5
41 - 43 - 47
16^8 - 64^5 = (4^3)^5 = 4^15 - 16^8=(4^2)^8 = 4^16
1/a^6
A subset.

27. What is a major arc?

28. How many multiples does a given number have?
Infinite.
4096
An arc is a portion of a circumference of a circle.
12sqrt2

29. What is the 'Solution' for a system of linear equations?
1/2 times 7/3
The point of intersection of the systems.
The set of elements found in both A and B.
Indeterminable.

30. Pi is a ratio of what to what?

31. 25^(1/2) or sqrt. 25 =
5 OR -5
4:5
(a + b)^2
Members or elements

32. 70 < all primes< 80
2sqrt6
71 - 73 - 79
2 & 3/7
Angle/360 x 2(pi)r

33. For what values should the domain be restricted for the function f(x) = sqrt(x + 8)
52
8
Its negative reciprocal. (-b/a)
1/2 times 7/3

34. What is the formula for compounded interest?
28. n = 8 - k = 2. n! / k!(n-k)!
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.
12sqrt2
1

35. 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).
F(x) + c
The set of elements which can be found in either A or B.
90pi

36. 1/2 divided by 3/7 is the same as
A central angle is an angle formed by 2 radii.
1/2 times 7/3
16.6666%
Its divisible by 2 and by 3.

37. Define an 'expression'.
An algebraic expression is a combination of one of more terms. Terms in an expression are separated by either addition or subtraction signs. (3xy - 4ab - -5cd - x^2 + x - 1)
C = (pi)d
An isosceles right triangle.
288 (8 9 4)

38. Is 0 even or odd?
55%
A = I (1 + rt)
All real numbers which can'T be expressed as a ratio of two integers - positive and negative (pi - -sqrt3)
Even

39. Can you add sqrt 3 and sqrt 5?
130pi
No - only like radicals can be added.
2.592 kg
(amount of decrease/original price) x 100%

40. What is the order of operations?
PEMDAS (Parentheses Exponents Multiplication/Division Addition/Subtraction)
1
The union of A and B.
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)

41. Formula to find a circle'S circumference from its radius?
The two xes after factoring.
Infinite.
C = 2(pi)r
Its divisible by 2 and by 3.

42. 30< all primes<40
4.25 - 6 - 22
75:11
31 - 37
54sqrt3. (divide the hexagon into 6 congruent equilateral triangles.

43. What percent of 40 is 22?
55%
3sqrt4
61 - 67
Sqrt 12

44. Surface area for a cylinder?
F(x) - c
2(pi)r^2 + 2(pi)rh
Two equal sides and two equal angles.
Area of the base X height = (pi)hr^2

45. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
(amount of decrease/original price) x 100%
Two equal sides and two equal angles.
6
12! / 5!7! = 792

46. When does a function automatically have a restricted domain (2)?
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.
10! / 3!(10-3)! = 120
72
F(x-c)

47. Define a 'monomial'
1
An expression with just one term (-6x - 2a^2)
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)
6 : 1 : 2

48. What does the graph (x+2)^2 + (y+2)^2 = 9 look like?
Its divisible by 2 and by 3.
y = (x + 5)/2
1
A circle centered at -2 - -2 with radius 3.

49. Can you simplify sqrt72?
Diameter(Pi)
7 / 1000
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
The set of elements which can be found in either A or B.

50. Formula to calculate arc length?
Arc length = (n/360) x pi(2r) where n is the number of degrees.
The third side is greater than the difference and less than the sum.
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...
9 & 6/7