Correct Answer: A

Rationale: To subtract mixed numbers, convert them to improper fractions. 8¼ = 33/4 and 1½ = 3/2. Subtracting, we get 33/4 - 3/2 = 33/4 - 6/4 = 27/4 = 6¾, which simplifies to 4¼. Therefore, the correct answer is 4¼. Choice B is incorrect as it represents the intermediate step of 6¾ before simplification. Choice C is incorrect as it is the result of the subtraction but not simplified. Choice D is incorrect as it is the original mixed number 7¼, not the simplified result.

Correct Answer: B

Rationale: The scale of 1:30 means that 1 inch on the plan represents 30 inches in actual size. If the width of the barn door on the plan is 3 inches, the actual width is calculated by multiplying 3 inches by the scale factor (30), giving 90 inches. To convert inches to feet, divide by 12 (since 12 inches = 1 foot), resulting in 90 inches · 12 = 7.5 feet. Therefore, the correct answer is 10 feet (option B), not 7.5 feet. Option A (90 inches) is the result before converting to feet, option C (9 feet) is the incorrect conversion if the initial calculation was done correctly, and option D (7.5 feet) is the incorrect conversion of the initial calculation.

Correct Answer: B

Rationale: Rationale: Given that 1 teaspoon is equal to 5ml, and the medication dosage is listed as 1/2 teaspoon, we need to find half of 5ml. 1/2 of 5ml = 5ml / 2 = 2.5ml Therefore, the equivalent dosage in milliliters for 1/2 teaspoon is 2.5ml.

Correct Answer: B

Rationale: To convert quarts to pints, we know that 1 quart is equivalent to 2 pints. Therefore, to find out how many pints are in 4 quarts, we multiply 2 pints by 4, which equals 8 pints. Hence, the correct answer is 8 pints. Choice A (2 pints) is incorrect because it represents the conversion of 1 quart, not 4 quarts. Choice C (16 pints) and Choice D (32 pints) are incorrect as they miscalculate the conversion by not considering the correct conversion factor of 2 pints per quart.

Correct Answer: B

Rationale: Rationale: - If the hand sanitizer contains 70% alcohol, it means that 70% of the 5ml used is pure alcohol. - To find the amount of pure alcohol present, we calculate 70% of 5ml: 0.7 * 5ml = 3.5ml. - Therefore, when 5ml of sanitizer are used, there are 3.5ml of pure alcohol present.