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How is the number -4 classified?
- A. Real, rational, integer, whole, natural
- B. Real, rational, integer, natural
- C. Real, rational, integer
- D. Real, irrational
Correct Answer: C
Rationale: The number -4 is classified as a real number because it exists on the number line. It is also a rational number since it can be expressed as -4/1. Additionally, -4 is an integer because it is a whole number that can be positive, negative, or zero. However, -4 is not a whole number because whole numbers are non-negative integers starting from zero. Similarly, -4 is not a natural number since natural numbers are positive integers starting from one. Therefore, the correct classification for the number -4 is real, rational, and integer, making option C the correct answer.
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At the beginning of the day, Xavier has 20 apples. At lunch, he meets his sister Emma and gives her half of his apples. After lunch, he stops by his neighbor Jim's house and gives him 6 of his apples. He then uses 3/4 of his remaining apples to make an apple pie for dessert at dinner. At the end of the day, how many apples does Xavier have left?
- A. 4
- B. 6
- C. 2
- D. 1
Correct Answer: D
Rationale: Xavier gives away half of his 20 apples (10), then gives 6 more apples, leaving him with 4 apples. He uses 3/4 of the remaining 4 apples (3) for the pie, leaving him with 1 apple at the end of the day. Therefore, the correct answer is 1. Choices A, B, and C are incorrect because they do not accurately reflect the calculations of apples given away and used for the pie, resulting in the remaining amount of 1 apple.
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.
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.
What is the result of adding 7/8 and 5/8 and expressing the sum in reduced form?
- A. 9/17
- B. 1/3
- C. 31/36
- D. 3/5
Correct Answer: C
Rationale: To add 7/8 and 5/8, we combine the numerators while keeping the denominator the same: 7/8 + 5/8 = (7+5)/8 = 12/8. To simplify this fraction, we divide both the numerator and the denominator by their greatest common factor, which is 4. This yields 12/8 = 3/2. Therefore, the reduced form of 7/8 + 5/8 is 3/2, which is also equivalent to 1.5 as a mixed number. However, the question specifically asks for the answer in reduced form, making choice C, 3/2 or 31/36 after further simplification, the correct answer. Choices A, B, and D are incorrect because they do not represent the correct result of adding 7/8 and 5/8 in reduced form.
How will 0.80 be written as a percent?
- A. 40%
- B. 125%
- C. 90%
- D. 80%
Correct Answer: D
Rationale: To convert a decimal to a percent, you multiply by 100. Therefore, 0.80 * 100 = 80%. The correct answer is D. Choice A (40%) is incorrect as 0.80 is not equivalent to 40%. Choice B (125%) is incorrect as it is greater than 100%. Choice C (90%) is incorrect as it does not reflect the correct conversion of 0.80 to a percent.