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.

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.

Correct Answer: A

Rationale: The correct answer is A: 'A number divisible by only 1 and itself.' A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. This definition aligns with choice A. Choice B is incorrect because not all prime numbers are divisible by 2 and 3. Choice C is incorrect as prime numbers are not divisible by any number other than 1 and themselves. Choice D is incorrect because a prime number has exactly two factors, 1 and itself, not three factors.

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.

Correct Answer: B

Rationale: To find the sale price after a 15% discount, you calculate 15% of $78, which is $11.70. Subtracting $11.70 from the original price gives $66.30. Since the price is typically rounded, the estimated sale price is $66. Choice A, $12, is too low and does not reflect a 15% discount off $78. Choice C, $22, and choice D, $69, are also incorrect as they do not accurately estimate the sale price after a 15% discount.