Correct Answer: A

Rationale: To calculate the total rainfall for May, June, and July, we add the rainfall amounts for each month: 3.2 inches (May) + 2.5 inches (June) + 3.3 inches (July) = 9.0 inches. Therefore, the correct answer is A. Choice B (8.4 inches) is incorrect as it does not account for the correct sum of rainfall for the specified months. Choice C (7.5 inches) is incorrect as it does not include the accurate total rainfall for May, June, and July. Choice D (10.5 inches) is incorrect as it provides a total that exceeds the actual combined rainfall for the given months.

Correct Answer: A

Rationale: Choice A represents no correlation between two variables as it states that as a student's class attendance decreases, the student's overall grade remains the same. This scenario shows no relationship between class attendance and grade. In contrast, choices B, C, and D show clear correlations between the variables mentioned. Choice B indicates a negative correlation between exercise hours and weight gain, choice C indicates a negative correlation between miles driven and gasoline in the tank, and choice D indicates a positive correlation between water intake and plant growth rate, making them all examples of correlated relationships.

Correct Answer: B

Rationale: To find the sale price after a 15% discount, you calculate 15% of $78, which is $11.70. Subtracting $11.70 from the original price gives $66.30. Since the price is typically rounded, the estimated sale price is $66. Choice A, $12, is too low and does not reflect a 15% discount off $78. Choice C, $22, and choice D, $69, are also incorrect as they do not accurately estimate the sale price after a 15% discount.

Correct Answer: D

Rationale: After deducting $172 weekly for taxes ($72 + $35 + $65), the teacher's net weekly income is $558. Over 4 weeks, the total income is $2,232.00. Choice A is incorrect as it does not account for the taxes deducted. Choice B is incorrect as it overestimates the income by not deducting the taxes. Choice C is incorrect as it also does not consider the tax deductions.

Correct Answer: D

Rationale: To find the cost of one syringe, divide the total cost by the number of syringes: $660.00 · 55 = $12. Therefore, the cost of four syringes is 4 x $12 = $48. Choices A, B, and C are incorrect because they do not correctly calculate the cost per syringe or the total cost of four syringes.