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.

Correct Answer: A

Rationale: The ratio 4:3 implies that for every 4 oz of yogurt, there are 3 oz of toppings. To find the amount of yogurt when the friend has 4.5 oz of toppings, we use the proportion: (4/3) 4.5 = 6 oz. Therefore, the amount of yogurt in their dessert is 6 oz. Choices B, C, and D are incorrect as they do not reflect the correct calculation based on the given ratio.

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: B

Rationale: The total cost (T) consists of the initial charge of $40 plus the additional charges based on the number of tablecloths. The correct expression for T is T = 5c + 3.5r + 40. This accounts for the $5 per circular tablecloth (5c), $3.50 per rectangular tablecloth (3.5r), and the initial $40 charge. Choice A is incorrect as it subtracts the initial charge instead of adding it. Choice C is also incorrect as it subtracts the initial charge and has the coefficients in the wrong positions. Choice D adds the initial charge at the end instead of at the beginning, making it incorrect. Therefore, choice B is the correct representation of the total cost to rent tablecloths.

Correct Answer: C

Rationale: The correct answer is C: 'As elevation increases, temperature decreases.' In a negative correlation, the variables move in opposite directions. As elevation rises, temperature tends to decrease. Choice A is incorrect because a negative correlation implies that as one variable increases, the other decreases. Choices B and D are incorrect because they suggest that temperature either remains the same or increases as elevation decreases or increases, which is inconsistent with a negative correlation.