What is the median of the set of numbers {2, 3, 9, 12, 15}?
- A. 3
- B. 9
- C. 12
- D. 15
Correct Answer: B
Rationale: The median represents the middle value in an ordered set of numbers. To find the median, the numbers need to be arranged in ascending order: {2, 3, 9, 12, 15}. Since the set has an odd number of elements, the median will be the middle value, which is 9 in this case. Choice A (3) and Choice D (15) are incorrect as they do not fall in the middle of the ordered set. Choice C (12) is also incorrect as it is not the middle value in this particular set.
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Which of the following equations does not represent a function?
- A. y = x^2
- B. y = sqrt(x)
- C. x = y^2
- D. y = 2x + 1
Correct Answer: C
Rationale: An equation represents a function if each input (x-value) corresponds to exactly one output (y-value). In the equation x = y^2, for a single x-value, there are two possible y-values (positive and negative square root), violating the definition of a function. This violates the vertical line test, where a vertical line intersects the graph in more than one point for non-functions. Choices A, B, and D all pass the vertical line test and represent functions, making them incorrect answers.
What is 1.25 as a fraction?
- A. 1 1/4
- B. 5/4
- C. 4/5
- D. 25/20
Correct Answer: B
Rationale: To convert a decimal to a fraction, we note that 1.25 can be expressed as 1 + 0.25. Since 0.25 is equivalent to 25/100 or 1/4, we add 1 whole to 1/4 to get 1 1/4, which simplifies to 5/4. Therefore, 1.25 as a fraction is 5/4. Choice A (1 1/4) is the mixed number form of 5/4. Choice C (4/5) and Choice D (25/20) are incorrect fractions that do not represent 1.25.
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.
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.