Correct Answer: A

Rationale: To find the cost of 1 book, divide the total cost by the number of books: $4 / 3 = $1.33 per book. To determine the cost of 6 books, multiply the cost per book by 6: $1.33 * 6 = $8. Therefore, purchasing 6 books will cost $8. Choice B, $12, is incorrect as it incorrectly doubles the cost of 3 books. Choice C, $6, is incorrect as it is half the cost of 3 books. Choice D, $10, is incorrect as it does not accurately calculate the cost of 6 books based on the given information.

Correct Answer: D

Rationale: To find the amount of medication delivered in one hour, we first calculate the amount delivered in one minute by multiplying the number of drops per minute (40) by the volume of each drop (0.05 milliliters). This gives us 2 milliliters per minute. Then, to find the total amount delivered in one hour, we multiply 2 milliliters per minute by the number of minutes in an hour (60), resulting in 120 milliliters. Therefore, the correct answer is 120 milliliters. Choices A, B, and C are incorrect as they do not correctly calculate the total volume of medication delivered in one hour.

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.

Correct Answer: A

Rationale: When multiplying decimal numbers like 44.44 and 55.55, align them properly and multiply each place accurately. To find the product of 44.44 and 55.55, you get 2,468.64. Therefore, the correct answer is choice A, 2,468.64. Choice B, 2,500.00, is incorrect as it is the result of rounding up. Choice C, 2,450.45, is incorrect as it is not the result of multiplying 44.44 by 55.55. Choice D, 2,470.00, is incorrect as it is not the correct product of 44.44 and 55.55.

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.