Correct Answer: A

Rationale: When 45% of the babies were girls, it means the remaining 55% were boys. To determine the number of boys, calculate 55% of 76, which equals approximately 41.8, rounding up to 42. Therefore, 42 boys were born last night at the hospital. Choice B, C, and D are incorrect as they do not reflect the accurate calculation of the number of boys born.

Correct Answer: C

Rationale: To convert grams to milligrams, you need to multiply by 1000 since there are 1000 milligrams in a gram. So, to convert 63 grams to milligrams, you would calculate 63 * 1000 = 63,000 milligrams. Therefore, the correct answer is 63,000 mg. Choice A (630 mg) is incorrect as it would be the converted value if the original amount was 0.63 grams. Choice B (63 mg) is incorrect as it is the same value as the original grams. Choice D (63,000 mg) is incorrect as it is the same as the correct answer, but with a comma which is not standard when expressing numerical values.

Correct Answer: D

Rationale: The difference between the original price ($200) and the new price ($150) is $50. To find the percentage decrease, divide the difference by the original price and multiply by 100: ($50 / $200) 100 = 25%. Therefore, the correct answer is D, meaning the price decreased by 25%. Choices A, B, and C are incorrect as they do not accurately represent the percentage decrease in price.

Correct Answer: B

Rationale: To solve the equation 4y - 6 = 14 for y, isolate y by adding 6 to both sides: 4y = 14 + 6 => 4y = 20. Then, divide by 4 to solve for y: y = 20 · 4 = 5. Therefore, the correct answer is 5. Choice A is incorrect as it does not represent the correct solution to the equation. Choice C is incorrect as it is not the solution obtained after correctly solving the equation. Choice D is incorrect as it is not the correct solution to the given equation.

Correct Answer: C

Rationale: To find the percentage of 8 in 40, divide 8 by 40 to get 0.2. Multiply this result by 100 to convert it to a percentage: 0.2 100 = 10%. Therefore, 8 is 10% of 40, making choice C the correct answer. Choices A, B, and D are incorrect percentages calculated from incorrect divisions and multiplications.