Correct Answer: A

Rationale: To calculate the dose for a 2-year-old child using Fred's rule, we substitute the child's age (24 months) and the adult dose (15 mg) into the formula: (24 x 15) / 150 = 2.4 mg. Therefore, the correct answer is A, representing 2.4 mg for a 2-year-old child. Choice B is incorrect as it does not match the calculated dose. Choice C is incorrect as it does not consider the formula provided. Choice D is incorrect as it does not reflect the correct calculation based on the given information.

Correct Answer: B

Rationale: To compare who ate more of their meal, we need to convert the fractions to the same format. John ate 75% of his lunch, which is equivalent to 3/4. Sally ate 5/8 of her lunch. Comparing 3/4 to 5/8, we find that 3/4 is greater than 5/8. Therefore, John ate more of his meal than Sally. Choice B, John, is the correct answer. Choices A, C, and D are incorrect because John consumed 3/4 of his lunch, which is more than 5/8 that Sally consumed, making him the one who ate more of his meal.

Correct Answer: C

Rationale: To convert a percentage to a decimal, divide by 100. In this case, to convert 76.3% to a decimal, you move the decimal point two places to the left, resulting in 0.763. Therefore, the correct answer is C. Choice A (0.0763) is incorrect as it represents 7.63% as a decimal. Choice B (7) and Choice D (7.63) are not correct conversions of the given percentage to a decimal.

Correct Answer: C

Rationale: To add mixed numbers, first add the whole numbers together, then add the fractions. 6 + 8 = 14. For the fractions: 3/4 + 1/6 = (18 + 4) / 24 = 22/24 = 11/12. Therefore, 6 & 3/4 + 8 & 1/6 equals 14 & 11/12. Choice A is incorrect as it does not represent the correct sum. Choice B is incorrect because it does not match the correct result. Choice D is incorrect as it simplifies to 12 & 1/6, not 12 & 3/24.

Correct Answer: B

Rationale: The opposite of a number is the number that, when added to it, results in zero. In this case, the opposite of -3 is a number that, when added to -3, gives 0. Therefore, the opposite of -3 is 3, as -3 + 3 = 0. Choice A, -6, is incorrect because -3 + (-6) = -9, not zero. Choice C, 0, is the additive inverse of 0, not -3. Choice D, 6, is also incorrect as -3 + 6 = 3, not zero.