Correct Answer: B

Rationale: To find the final concentration, first, calculate the total volume of the solution (2 ml + 8 ml = 10 ml). Then, determine the concentration by dividing the volume of the concentrated medication by the total volume and multiplying by 100%: (2 ml / 10 ml) * 100% = 20%. Therefore, the correct answer is B. Choice A (16.67%) is incorrect as it does not represent the correct calculation. Choices C (25%) and D (50%) are both incorrect as they do not reflect the accurate concentration resulting from the dilution process.

Correct Answer: A

Rationale: The Roman numeric system does not use place value as the Arabic, Decimal, and Binary systems do. In the Roman numeral system, the value of each symbol is independent of its position, unlike in the other systems where the position of a digit affects its value. This unique characteristic of Roman numerals distinguishes them from place-value systems like Arabic, Decimal, and Binary. Therefore, the correct answer is Roman (Choice A). Choices B, C, and D (Arabic, Decimal, and Binary) all utilize place value, where the position of a digit within a number determines its value, unlike Roman numerals.

Correct Answer: A

Rationale: First, calculate the total cost of the 20 stamps bought at 29¢ each: 20 stamps * 29¢ = $5.80. Next, calculate the total cost of the 40 stamps bought at 42¢ each: 40 stamps * 42¢ = $16.80. The total cost of all stamps is $5.80 + $16.80 = $22.60. If Tamison gave $25 to the postal worker, her change is $25 - $22.60 = $2.40. Therefore, the correct answer is A. Option B, C, and D are incorrect as they do not reflect the correct change Tamison received after buying the stamps.

Correct Answer: D

Rationale: Adding the given numbers together: 34 + 4 + 234 = 272. The correct sum is 272. Choice A, 70.2, is incorrect as it does not reflect the accurate addition of the numbers. Choice B, 230.72, is incorrect as well. Choice C, 234.74, is also incorrect since the correct sum is 272, not 234.74.

Correct Answer: A

Rationale: There are 1,000 milliliters in a liter. To convert 2,500 milliliters to liters, you divide by 1,000: 2,500 milliliters / 1,000 = 2.5 liters. Therefore, choice A, '2.5 liters,' is the correct answer. Choice B, '25 liters,' is incorrect as it would be the result if you mistakenly multiplied instead of dividing. Choice C, '250 liters,' is incorrect as it is 100 times the correct answer. Choice D, '25,000 liters,' is significantly higher and not a conversion error but an order of magnitude error.