Correct Answer: A

Rationale: The correct answer is y = 3x. By examining the table provided, we can see that for each increase of 1 in x, y increases by 3. This consistent pattern indicates that y is three times the value of x, leading to the equation y = 3x. Choices B, C, and D do not match the pattern observed in the table and are therefore incorrect.

Correct Answer: B

Rationale: To calculate a 30% decrease in 340 mg, you multiply 340 by 0.3, which equals 102 mg. Subtracting this from the current dosage gives 340 - 102 = 238 mg. Therefore, the correct answer is 238 mg. Choice A (70 mg) is incorrect because it represents a 70% decrease, not 30%. Choice C (270 mg) is incorrect as it does not reflect the correct calculation for a 30% decrease. Choice D (340 mg) is the initial dosage and not the reduced dosage after a 30% decrease.

Correct Answer: D

Rationale: The correct answer is D, which is 4 quarts in a gallon. In the US customary system, there are 4 quarts in a gallon. Choice A is incorrect as it represents the equivalent of a quart, not a gallon. Choice B and C are incorrect as they are smaller quantities than a gallon and do not match the conversion of quarts to a gallon.

Correct Answer: B

Rationale: To find the total height of the stacked bookcases, you need to add the heights of the two bookcases: 32.75 inches + 17.25 inches = 50 inches. Therefore, the correct answer is 50 inches. Choice A (49.5 inches) is incorrect as it does not consider rounding off the total height. Choices C (48 inches) and D (51 inches) are incorrect as they do not accurately calculate the sum of the heights of the two bookcases.

Correct Answer: B

Rationale: ollow the order of operations (PEMDAS: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right)): Multiply: 7 3 = 21, and 4 2 = 8 Perform addition and subtraction: 6 + 21 - 8 = 19 Thus, the simplified expression equals 19.