What percentage of 40 is 8?

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.

Correct Answer: A

Rationale: The correct answer is A: 32,000 ounces. A ton is equivalent to 2,000 pounds. Since each pound contains 16 ounces, you can calculate the total number of ounces in a ton by multiplying 2,000 pounds by 16 ounces, which equals 32,000 ounces. Choice B (30,000 ounces), Choice C (35,000 ounces), and Choice D (40,000 ounces) are incorrect because they do not correctly calculate the number of ounces in a ton based on the conversion of pounds to ounces.

Correct Answer: A

Rationale: To calculate the number of diapers needed in a year with 6 diaper changes per day, multiply the daily diaper changes (6) by the days in a year (365): 6 x 365 = 2190 diapers required. This calculation ensures an ample supply of diapers for maintaining the infant's hygiene and comfort. The other choices are incorrect because they do not accurately account for the number of diaper changes per day multiplied by the days in a year. Choice B (2100 diapers) is too low, while choices C (2160 diapers) and D (2140 diapers) are too high based on the calculation. Understanding the frequency and quantity of diaper changes is crucial for supporting the infant's health and well-being. Therefore, the correct answer is 2190 diapers.

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: A

Rationale: First, convert the child's weight from pounds to kilograms: 44 lb · 2.2 = 20 kg. Next, calculate the required dosage: 20 kg 20 mg/kg = 400 mg. Since each tablet contains 80 mg, divide the total dosage by the dosage per tablet: 400 mg · 80 mg/tablet = 5 tablets. Therefore, the correct answer is 5 tablets. Choice B is incorrect because it does not account for the actual number of tablets needed. Choice C is incorrect as it is an underestimation of the required tablets. Choice D is incorrect as it is an underestimation of the required tablets.

Correct Answer: B

Rationale: To convert yards to feet, you multiply by 3, as 1 yard is equal to 3 feet. Therefore, 3 yards equals 3 x 3 = 9 feet. Choice A (18 feet) is incorrect because it multiplies by 2 instead of 3. Choice C (12 feet) is incorrect as it multiplies by 4 instead of 3. Choice D (27 feet) is incorrect as it multiplies by 9 instead of 3.

Correct Answer: C

Rationale: To find the volume required, divide the prescribed dose (60 mg) by the concentration available (80 mg/mL): 60 mg · 80 mg/mL = 0.75 mL. Therefore, 0.75 mL is the correct amount to administer. Choice A (1 ml) is incorrect as it does not consider the concentration of the solution. Choice B (0.5 ml) is incorrect as it is half the correct amount. Choice D (1.25 ml) is incorrect as it is more than the calculated correct amount.

Correct Answer: C

Rationale: To determine the number of trees, reduce the field dimensions by 10 meters (5 meters of space on each side). The effective area is 640 meters 770 meters. Each tree occupies 10 meters 10 meters. Dividing the effective area by the space for each tree gives: (640 770) · (10 10) = 286 trees. Choice A, B, and D are incorrect because they do not consider the reduction in field dimensions and the space required for each tree.

Correct Answer: B

Rationale: With y = 4 and x = 3, the expression is y x³. Substituting the values, we get 4 3³ = 4 27 = 108. Therefore, the correct answer is 108. Option A (-108) is incorrect because the negative sign is not part of the result. Option C (27) is incorrect as it only represents x³ without considering the value of y. Option D (4) is incorrect as it represents the initial value of y, not the result of y x³.