Correct Answer: D

Rationale: The correct answer is D: 17.8 cm. To convert inches to centimeters, you can use the conversion factor 1 inch = 2.54 cm. Therefore, 7 inches is equal to 7 * 2.54 = 17.78 cm, which rounds to 17.8 cm. Choices A, B, and C are incorrect because they do not correspond to the correct conversion of 7 inches to centimeters.

Correct Answer: A

Rationale: Rational numbers are those that can be written as a simple fraction, including whole numbers and decimals that either terminate or repeat. Irrational numbers, on the other hand, cannot be expressed as fractions. Choice B is incorrect because not all rational numbers necessarily terminate or repeat. Choice C is incorrect as it oversimplifies the concept of rational and irrational numbers by only considering whole numbers and decimals. Choice D is incorrect as it inaccurately defines rational and irrational numbers solely based on decimals terminating or repeating, excluding the broader category of fractions.

Correct Answer: C

Rationale: The correct order of operations dictates solving division and multiplication before addition and subtraction. Therefore, following the order: (12 · 3) 4 - 1 + 23 = 4 4 - 1 + 23 = 16 - 1 + 23 = 38. Choice A (6) results from adding and subtracting before division and multiplication. Choice B (21) results from incorrect placement of parentheses. Choice D (23) is the last number in the expression and does not reflect the cumulative result of the operations.

Correct Answer: A

Rationale: To convert yards to feet, you need to know that 1 yard is equal to 3 feet. Therefore, to convert yards to feet, you multiply the number of yards by 3. To convert feet to yards, you divide the number of feet by 3. Choice A correctly states that you should multiply yards by 3 to get feet and divide feet by 3 to get yards. Choices B, C, and D provide incorrect conversion factors, leading to inaccurate results.

Correct Answer: C

Rationale: To find the amount the friend paid, you can set up the equation 2x - 2000 = 48000, where x represents the amount the friend paid. Solving this equation gives x = $25,000. Therefore, the friend paid $25,000. Choice A ($23,000) is incorrect because it does not account for the $2,000 difference mentioned in the question. Choice B ($46,000) is incorrect because it is double the amount needed. Choice D ($50,000) is incorrect as it does not consider the $2,000 less mentioned in the question.