When the weights of the newborn babies are graphed, the distribution of weights is symmetric with the majority of weights centered around a single peak. Which of the following describes the shape of this distribution?

Correct Answer: C

Rationale: The correct answer is C: Bell-shaped. A symmetric distribution with a single peak is characteristic of a bell-shaped distribution, also known as a normal distribution. This distribution forms a symmetrical, bell-like curve when graphed. Choice A, 'Uniform,' would describe a distribution where all values have equal probability. Choice B, 'Bimodal,' would indicate a distribution with two distinct peaks. Choice D, 'Skewed right,' suggests a distribution where the tail on the right side is longer or more pronounced, unlike the symmetrical bell-shaped distribution described in the question.

Correct Answer: D

Rationale: To find the area of a circle, we use the formula A = πr², where r is the radius of the circle. In this case, the diameter is 9 inches, so the radius is half of the diameter, which is 4.5 inches. Substituting the radius into the formula, we get A = π(4.5)² = 20.25 πin². Therefore, the correct answer is 20.25 πin². Choices A, B, and C are incorrect because they do not correctly calculate the area using the radius of the circle.

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.

Correct Answer: D

Rationale: In this math problem, we are asked to find the cost of four syringes given that a box of 55 syringes costs $660. To solve this problem, we need to set up a proportion based on the relationship between the number of syringes and their cost. If 55 syringes cost $660, then we can set up the proportion: 55 syringes / $660 = 4 syringes / x Cross multiplying, we get: 55 * x = 4 * $660 x = (4 * $660) / 55 x = $48 Therefore, the correct answer is D) $48. Explanation for why the other options are incorrect: - Option A) $51 is incorrect because it is not proportional to the cost of 4 syringes compared to 55 syringes. - Option B) $26 is incorrect because it is too low for the cost of 4 syringes based on the given information. - Option C) $32 is incorrect because it does not align with the proportionality between the number of syringes and their cost in this scenario. Educational context: This question assesses the student's understanding of proportions and how to apply them in real-world scenarios involving cost and quantity relationships. It reinforces the importance of setting up and solving proportions accurately to find unknown values in similar situations. Understanding this concept is crucial for success in math and practical applications in various fields.

Correct Answer: C

Rationale: To convert kilograms to pounds, multiply the weight in kilograms by the conversion factor 2.2 (1 kg = 2.2 lbs). Therefore, 45 kg * 2.2 lbs/kg = 99 lbs. Choice A is incorrect because it is a miscalculation. Choice B is incorrect as it does not reflect the correct conversion. Choice D is incorrect as it is also a miscalculation of the conversion.