Correct Answer: D

Rationale: The Roman numeral MDXVI translates to 1516 in Arabic numerals. The Roman numeral 'M' represents 1000, 'D' represents 500, 'X' represents 10, and 'VI' represents 6, which adds up to 1516. Therefore, the correct answer is 1516. Choices A, B, and C are incorrect as they do not match the Roman numeral MDXVI.

Correct Answer: C

Rationale: Let Lulu's sister's age be x. According to the given information, x = 15 (cousin's age) + 7 = 22. So, Lulu's sister is 22 years old. Since Lulu is 5 years younger than her sister, Lulu's age is 22 - 5 = 17. Therefore, Lulu is 17 years old. Choices A, B, and D are incorrect because they do not correspond to the calculations based on the information provided in the question.

Correct Answer: D

Rationale: If 20 students are divided into pairs, there would be 10 pairs in total (20 students / 2 = 10 pairs). Since each pair receives 10 pencils, the total number of pencils needed is calculated by multiplying the number of pairs (10 pairs) by the number of pencils each pair receives (10 pencils per pair), resulting in 100 pencils required. Therefore, the correct answer is 100 pencils. Choices A, B, and C are incorrect because they do not consider the correct pairing of students or the total number of pencils needed for each pair.

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: To find 60% of 90, you multiply 90 by 0.60 (which is the decimal form of 60%). So, 90 * 0.60 = 54. Therefore, 60% of 90 is 54. Choice A is correct. Choice B, C, and D are incorrect as they do not reflect the correct calculation for finding 60% of 90.