Test your basic knowledge |

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. Solve the quadratic equation ax^2 + bx + c= 0
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
x^(4+7) = x^11
Its last two digits are divisible by 4.
12sqrt2

2. How to find the diagonal of a rectangular solid?
Undefined - because we can'T divide by 0.
52
1
Use Pythagorean theorem twice. (Once across the surface and then a is the diagonal of surface and b is an edge).

3. How to find the area of a sector?
9 & 6/7
$11 -448
Angle/360 x (pi)r^2
Undefined

4. What are complementary angles?
Two angles whose sum is 90.
70
12! / 5!7! = 792
9 & 6/7

5. The four angles around a point measure y - 2y - 35 and 55 respectively. What is the value of y?
A subset.
90
Angle/360 x 2(pi)r
71 - 73 - 79

6. What is the 'Solution' for a set of inequalities.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
The graph of 3(x - 1)^2 is a translation (shift) of the graph one unit or space to the right.
The overlapping sections.
x^(6-3) = x^3

7. Whats the difference between factors and multiples?
18
No - only like radicals can be added.
Factors are few - multiples are many.
The sum of its digits is divisible by 3.

8. 1:1:sqrt2 is the ratio of the sides of what kind of triangle?
37.5%
A subset.
A 30-60-90 triangle.
An isosceles right triangle.

9. 10^6 has how many zeroes?
A set with no members - denoted by a circle with a diagonal through it.
(amount of increase/original price) x 100%
6
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.

10. 1:sqrt3:2 is the ratio of the sides of what kind of triangle?
55%
An isosceles right triangle.
48
A 30-60-90 triangle.

11. What is the third quartile of the following data set: 44 - 58 - 63 - 63 - 68 - 70 - 82
70
87.5%
13
Arc length = (n/360) x pi(2r) where n is the number of degrees.

12. Define a 'monomial'
[(7+ sqrt93) /2] - [(7 - sqrt93) / 2]
A circle centered on the origin with radius 8.
An expression with just one term (-6x - 2a^2)
72

13. 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
(amount of decrease/original price) x 100%
18
The set of elements found in both A and B.
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

14. 1/8 in percent?
48
71 - 73 - 79
An arc is a portion of a circumference of a circle.
12.5%

15. 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.
N! / (n-k)!
61 - 67
$11 -448

16. Volume for a cylinder?
Sector area = (n/360) X (pi)r^2
1:sqrt3:2
Its last two digits are divisible by 4.
Area of the base X height = (pi)hr^2

17. Formula to calculate arc length?
Yes - like radicals can be added/subtracted.
28. n = 8 - k = 2. n! / k!(n-k)!
(a + b)^2
Arc length = (n/360) x pi(2r) where n is the number of degrees.

18. 25^(1/2) or sqrt. 25 =
1
3
5 OR -5
The curve opens upward and the vertex is the minimal point on the graph.

19. What are the rational numbers?
...multiply by 100.
All numbers which can be expressed as a ratio of two integers. (All integers and fractions.) (-2 - 1 - .25 - 1/2)
500
16.6666%

20. How many digits are there between the decimal point and the first even digit in the decimal equivalent of 1/[(2^8)(5^3)]
The union of A and B.
N! / (n-k)!
1.7
0

21. What is the graph of f(x) shifted right c units or spaces?
71 - 73 - 79
Its last two digits are divisible by 4.
90 degrees
F(x-c)

22. What is the 'Range' of a function?
The shortest arc between points A and B on a circle'S diameter.
A grouping of the members within a set based on a shared characteristic.
The set of output values for a function.
1

23. From a box of 12 candles - you are to remove 5. How many different sets of 5 candles could you remove?
Relationship cannot be determined (what if x is negative?)
1.0843 X 10^11
52
12! / 5!7! = 792

24. If 10800 is invested at a simple interest rate of 4% - what is the value of the investment after 18 months?
3 - -3
$11 -448
A subset.
Sqrt 12

25. What are the smallest three prime numbers greater than 65?
The sum of digits is divisible by 9.
72
(p + q)/5
67 - 71 - 73

26. 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?
10! / (10-3)! = 720
An arc is a portion of a circumference of a circle.
Its divisible by 2 and by 3.
A subset.

27. Surface area for a cylinder?
0
.0004809 X 10^11
2(pi)r^2 + 2(pi)rh
413.03 / 10^4 (move the decimal point 4 places to the left)

28. What is a set with no members called?
The longest arc between points A and B on a circle'S diameter.
(b + c)
The empty set - denoted by a circle with a diagonal through it.
67 - 71 - 73

29. 6w^2 - w - 15 = 0
3/2 - 5/3
IV
90pi
Lies opposite the greater angle

30. If Madagascar'S exports totaled 1.3 billion in 2009 - and 4% came from China - what was the value in millions of the country'S exports to China?
9 : 25
Pi is the ratio of a circle'S circumference to its diameter.
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.
52

31. How many 3-digit positive integers are even and do not contain the digit 4?
2(pi)r^2 + 2(pi)rh
288 (8 9 4)
Ax^2 + bx + c where a -b and c are constants and a /=0
1

32. What does scientific notation mean?
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
N! / (k!)(n-k)!
The second graph is less steep.
90pi

33. When does a function automatically have a restricted domain (2)?
90pi
52
12sqrt2
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

34. To convert a decimal to a percent...
...multiply by 100.
Diameter(Pi)
12sqrt2
90

35. Nine coins are tossed simultaneously. In how many of the outcomes will the fourth coin tossed show heads?
2^9 / 2 = 256
The angle intersecting the circumference is always the largest angle - and is always 90 degrees.
The curve opens downward and the vertex is the maximum point on the graph.
1

36. What is the set of elements which can be found in either A or B?
Area of the base X height = (pi)hr^2
The union of A and B.
(12/2) x (sqrt15 / sqrt5) = 6sqrt3
A circle centered on the origin with radius 8.

37. A number is divisible by 4 is...
When the function is not defined for all real numbers -; only a subset of the real numbers.
72
Its last two digits are divisible by 4.
Ax^2 + bx + c where a -b and c are constants and a /=0

38. Which quandrant is the lower right hand?
An isosceles right triangle.
37.5%
IV
31 - 37

39. The objects in a set are called two names:
48
Members or elements
No - only like radicals can be added.
C = 2(pi)r

40. 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?
x = [(-b)+/- (sqrt b^2 - 4ac)]/2a
The curve opens upward and the vertex is the minimal point on the graph.
9 : 25
A central angle is an angle formed by 2 radii.

41. x^6 / x^3
27^(-4)
x^(6-3) = x^3
1:sqrt3:2
The union of A and B.

42. 5/6 in percent?
A set with a number of elements which can be counted.
Expressing a number as the product of a decimal between 1 and 10 - and a power of 10.
II
83.333%

43. A number is divisible by 3 if ...
9 : 25
6 : 1 : 2
The sum of its digits is divisible by 3.
When we need to avoid having a zero in the denominator or avoid taking the square root of a number.

44. If 8 schools are in a conference - how many games are played if each team plays each other exactly once?
C = 2(pi)r
True
2 & 3/7
28. n = 8 - k = 2. n! / k!(n-k)!

45. A triangle is inscribed in a semi circle with legs 5 and 12. What is the circumfermence of the semicircle?
13pi / 2
The set of elements found in both A and B.
A = I (1 + rt)
0

46. Max and Min lengths for a side of a triangle?
(p + q)/5
An infinite set.
The third side is greater than the difference and less than the sum.
Indeterminable.

47. 1/6 in percent?
Yes - because you can factor out a perfect square (36). Sqrt(36 x 2) = sqrt36 X sqrt2 = 6sqrt2.
16.6666%
180 degrees
4:9. The ratio of the areas of two similar triangles equals the square of the ratio of the corresponding sides.

48. 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?
2.592 kg
... the square of the ratios of the corresponding sides.
31 - 37
1:sqrt3:2

49. (-1)^2 =
500
The empty set - denoted by a circle with a diagonal through it.
A reflection about the axis.
1

50. What is the formula for computing simple interest?
A = I (1 + rt)
41 - 43 - 47
70
It is a function defined by more than one equation - where each equation applies to a different part of the domain of the function.