Nokea
What is the domain for the function y = 1/x?
- A. All real numbers except 0
- B. x > 0
- C. x = 0
- D. x = 1
Correct Answer: A
Rationale: The domain of a function consists of all possible input values that produce a valid output. In the case of y = 1/x, the function is undefined when x = 0 because division by zero is not defined in mathematics. Therefore, the correct domain for y = 1/x is all real numbers except 0 (Choice A). Choice B, x > 0, is incorrect because it excludes the value x = 0. Choice C, x = 0, is also incorrect as x = 0 is not a valid part of the domain due to the function being undefined at this point. Choice D, x = 1, is unrelated to the domain of the function and does not represent the set of valid input values for y = 1/x.
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What are all the factors of 12?
- A. 12, 24, 36
- B. 1, 2, 4, 6, 12
- C. 12, 24, 36, 48
- D. 1, 2, 3, 4, 6, 12
Correct Answer: D
Rationale: The factors of 12 are numbers that divide evenly into 12 without leaving a remainder. The correct factors of 12 are 1, 2, 3, 4, 6, and 12. Choice A (12, 24, 36) is incorrect as only 12 is a factor of 12. Choice B (1, 2, 4, 6, 12) includes all the correct factors of 12. Choice C (12, 24, 36, 48) is incorrect as 24, 36, and 48 are not factors of 12.
Which operation should be completed first in the expression 8 + 5 * 3?
- A. Multiplication
- B. Addition
- C. Division
- D. Subtraction
Correct Answer: A
Rationale: The correct answer is 'Multiplication.' In the expression 8 + 5 * 3, according to the order of operations (PEMDAS), multiplication should be done before addition. PEMDAS stands for Parentheses, Exponents, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right). Therefore, the multiplication operation should be completed first, making 5 * 3 equal to 15, and then the addition operation should be conducted to get the final result of 8 + 15, which equals 23. Choices B, C, and D are incorrect because in this expression, multiplication takes precedence over addition, division, and subtraction according to the order of operations.
Five of six numbers have a sum of 25. The average of all six numbers is 6. What is the sixth number?
- A. 8
- B. 10
- C. 11
- D. 12
Correct Answer: C
Rationale: To find the sum of all six numbers, we multiply the average (6) by the total numbers (6), which equals 36. Since the sum of five numbers is 25, the sixth number can be found by subtracting the sum of five numbers from the total sum: 36 - 25 = 11. Therefore, the sixth number is 11.
Choice A, 8, is incorrect because adding 8 to the sum of five numbers (25) would result in a total greater than the correct sum of all six numbers (36).
Choice B, 10, is incorrect because adding 10 to the sum of five numbers (25) would also result in a total greater than the correct sum of all six numbers (36).
Choice D, 12, is incorrect because adding 12 to the sum of five numbers (25) would exceed the correct sum of all six numbers (36).
What is the mode of the set of numbers {4, 4, 5, 7, 8}?
- A. 4
- B. 5
- C. 7
- D. 8
Correct Answer: A
Rationale: The mode of a set of numbers is the value that appears most frequently. In the given set {4, 4, 5, 7, 8}, the number 4 appears twice, which is more frequent than any other number. Therefore, the mode of this set is 4. Choice B, 5, is incorrect as it only appears once in the set. Choices C and D, 7 and 8 respectively, also appear only once each, making them less frequent than the number 4.
What is the value of the sum of 3/4 and 5/8?
- A. 1 3/8
- B. 1 1/2
- C. 1 7/8
- D. 1 5/8
Correct Answer: D
Rationale: To find the sum of fractions, they need to have a common denominator. In this case, the common denominator is 8. So, 3/4 = 6/8. Adding 6/8 and 5/8 gives 11/8, which simplifies to 1 3/8. Therefore, the correct answer is 1 3/8, which corresponds to choice A. Choices B, C, and D are incorrect as they do not represent the correct sum of 3/4 and 5/8.