What is the mathematical expression for 'Twelve less than thrice a number'?
- A. 3x-12
- B. 12-3x
- C. 3-12x
- D. 12x-3
Correct Answer: A
Rationale: The phrase 'thrice a number' translates to 3x, and 'twelve less than' means subtracting 12 from it. Therefore, the correct expression is 3x-12. Choice B, '12-3x', represents '12 less than a number thrice,' which is the opposite of the given phrase. Choice C, '3-12x', does not correctly interpret the phrase provided. Choice D, '12x-3', represents 'a number thrice less than twelve,' which is not the same as the original phrase.
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If the width of a rectangle is 4 inches (in) and the area of the rectangle is 32 in², what is the length of the rectangle?
- A. 8 in
- B. 28 in
- C. 36 in
- D. 128 in
Correct Answer: A
Rationale: To find the length of the rectangle, we use the formula: Length = Area / Width. Substituting the values given, Length = 32 in² / 4 in = 8 in. Therefore, the correct answer is A. Choice B (28 in), Choice C (36 in), and Choice D (128 in) are incorrect because they do not correctly calculate the length based on the given width and area of the rectangle.
How many milliliters (mL) are there in a liter?
- A. 1000 mL
- B. 100 mL
- C. 10 mL
- D. 1 mL
Correct Answer: A
Rationale: The correct answer is A: 1000 mL. This is a standard conversion in the metric system where 1 liter is equivalent to 1000 milliliters. Choice B, 100 mL, is incorrect as it represents only a tenth of a liter. Choice C, 10 mL, is incorrect as it represents only a hundredth of a liter. Choice D, 1 mL, is significantly less than a liter, as it is only a thousandth of a liter.
Which of the following best describes the data set below? 1, 1, 2, 2, 2, 2, 3, 3, 7, 7, 8, 8, 8, 8, 9, 9
- A. Uniform
- B. Right-skewed
- C. Bimodal
- D. Left-skewed
Correct Answer: C
Rationale: The correct answer is C: Bimodal. A bimodal distribution has two distinct peaks or modes. In this data set, the numbers 2 and 8 appear more frequently than other numbers, creating two modes (2 and 8). Choices A, B, and D are incorrect. Option A, 'Uniform,' describes a distribution where all values have equal frequency, which is not the case in this data set. Options B and D, 'Right-skewed' and 'Left-skewed,' refer to distributions where the data is skewed towards one side, which is not observed in this dataset. Therefore, the data set is best described as bimodal.
What defines a proper fraction versus an improper fraction?
- A. Proper: numerator < denominator; Improper: numerator > denominator
- B. Proper: numerator > denominator; Improper: numerator < denominator
- C. Proper: numerator = denominator; Improper: numerator < denominator
- D. Proper: numerator < denominator; Improper: numerator = denominator
Correct Answer: A
Rationale: A proper fraction is characterized by having a numerator smaller than the denominator, while an improper fraction has a numerator larger than the denominator. Therefore, choice A is correct. Choice B is incorrect because it states the opposite relationship between the numerator and denominator for proper and improper fractions. Choice C is incorrect as it describes a fraction where the numerator is equal to the denominator, which is a different concept. Choice D is incorrect as it associates a numerator being smaller than the denominator with an improper fraction, which is inaccurate.
Four friends are sharing a pizza. One friend eats half of the pizza. The other three friends equally divide the rest among themselves. What portion of the pizza did each of the other three friends receive?
- A. 1/5
- B. 1/3
- C. 1/4
- D. 1/6
Correct Answer: D
Rationale: After one friend eats half of the pizza, there is half left. This remaining half is divided equally among three friends. To find the portion each of the other three friends receives, we divide 1/2 by 3, which equals 1/6. Therefore, each of the other three friends receives 1/6 of the pizza. Choice A, 1/5, is incorrect because the correct portion is 1/6. Choice B, 1/3, is incorrect as each of the three friends receives 1/6. Choice C, 1/4, is incorrect as well since the correct portion is 1/6.