Correct Answer: C

Rationale: First, convert the mixed number 1 (1/8) into an improper fraction: 1 (1/8) = 9/8. Now, simplify the expression: (1/4) (3/5) · (9/8). To divide by a fraction, multiply by its reciprocal: (1/4) (3/5) (8/9) = 24/180 = 2/15. Thus, the simplified expression is 2/15. Choice A (8/15) is incorrect because the correct answer is 2/15. Choice B (27/160) is incorrect as it is not the result of the given expression. Choice D (27/40) is incorrect as it does not match the simplified expression obtained.

Correct Answer: B

Rationale: The correct answer is B: 'The grades students received.' In this scenario, the grades students received are the dependent variable because they are influenced by the number of hours spent studying. The grades are the outcome that is being measured based on the manipulation or observation of the independent variable, which in this case is the number of hours spent studying. Choices A, C, and D are incorrect. The number of hours spent studying is the independent variable being manipulated or observed, the subjects students studied is not directly related to the dependent variable, and the number of students in the study is not the variable being measured or influenced by the independent variable.

Correct Answer: A

Rationale: To solve the expression, first calculate the multiplication: (3)(-4) = -12 and (3)(4) = 12. Then, substitute the results back into the expression: (-12) + 12 - 1 = -1. Therefore, the correct answer is A. Choices B, C, and D are incorrect as they do not result from the correct calculations of the given expression.

Correct Answer: A

Rationale: The correct answer is A: 1/2. When flipping a fair coin, there are two possible outcomes: heads or tails. The probability of getting heads is 1 out of 2 possible outcomes, which can be expressed as 1/2. Choice B, 1/3, is incorrect because a fair coin only has two sides. Choices C and D, 1/4 and 1/5, are also incorrect as they do not represent the correct probability of getting heads when flipping a coin.

Correct Answer: A

Rationale: To solve the equation 2x + 6 = 14, you first subtract 6 from both sides to isolate 2x. This gives 2x = 8. Then, divide by 2 on both sides to find x. Therefore, x = 4. Choices B, C, and D are incorrect as they do not correctly follow the steps of solving the equation.