Correct Answer: B

Rationale: To convert ounces to milliliters, we know that 1 ounce is approximately 30 mL. Therefore, 0.5 ounces would be half of that, which is 15 mL. So, 0.5 oz of perfume is equal to 15 mL. Choice A (10 mL), Choice C (20 mL), and Choice D (25 mL) are incorrect as they do not reflect the accurate conversion from ounces to milliliters.

Correct Answer: B

Rationale: To determine how much money Karen has left, we first calculate the total cost of the items she bought: $1.85 + $3.20 + $3.05 = $8.10. Subtracting this total cost from the initial amount she had, $40 - $8.10 = $31.90 left. Choice A, $30.95, is incorrect as it does not reflect the correct amount left after subtracting the total cost. Choice C, $32.10, is incorrect as it is the total cost of the items she bought, not the amount left. Choice D, $34.95, is incorrect as it does not consider the expenses incurred and subtracted from the initial amount.

Correct Answer: A

Rationale: To convert a percentage to a decimal, you divide by 100. In this case, 38% divided by 100 equals 0.38. Moving the decimal point two places to the left converts the percentage to a decimal. Choice B is incorrect because it incorrectly moves the decimal point one place to the left. Choice C is incorrect as it moves the decimal point three places to the left. Choice D is incorrect as it does not convert the percentage to a decimal.

Correct Answer: A

Rationale: To simplify the fraction 4/6, you can divide both the numerator and denominator by their greatest common divisor, which is 2. Dividing 4 by 2 gives 2, and dividing 6 by 2 gives 3. Therefore, the simplest ratio of 4/6 is 2:3. Choice B (4:7) is incorrect because it does not result from simplifying the fraction. Choice C (4:6) is incorrect as it represents the original fraction, not the simplest form. Choice D (3:5) is incorrect as it does not match the simplified ratio of 4/6.

Correct Answer: B

Rationale: To find the volume of the triangular shelf, first calculate the area of the triangle (1/2 * base * height) which is (1/2 * 40 * 30) = 600 sq cm. Then, multiply this area by the depth of the shelf (600 * 25) = 15000 cu cm. Therefore, the volume of each shelf is 3750 cu cm. Choice A, C, and D are incorrect as they do not correctly calculate the volume based on the dimensions provided.