Correct Answer: B

Rationale: To find the volume of a cube, you cube the length of one side. In this case, the side length is 3 cm, so the volume is calculated as 3 cm * 3 cm * 3 cm = 27 cm³. Therefore, the correct answer is 27 cm³. Choice A (9 cm³), Choice C (18 cm³), and Choice D (12 cm³) are incorrect as they do not correctly calculate the volume of a cube with a side length of 3 cm.

Correct Answer: C

Rationale: A valid hypothesis must be a testable statement that predicts a relationship between variables. Option C is the only statement that presents a clear cause-and-effect relationship between the amount of poison given and the time it takes for the rat to die. Option A is descriptive without predicting an outcome, option B is a question rather than a statement, and option D is a general fact about poison and rats, lacking a specific hypothesis for testing.

Correct Answer: A

Rationale: To simplify the expression (x^2 + 2x)/(x), we factor out x from the numerator to get x(x + 2) and then cancel the x in the denominator. This simplifies to x + 2, making choice A the correct answer. Choice B (x^2 + 2) is incorrect as it does not account for the division by x. Choice C (x(x + 2)) is also incorrect as it represents the factored form before cancellation. Choice D (1 + 2/x) is incorrect as it does not simplify the expression correctly.

Correct Answer: A

Rationale: The correct answer is 'Multiplication.' In the expression 8 + 5 * 3, according to the order of operations (PEMDAS), multiplication should be done before addition. PEMDAS stands for Parentheses, Exponents, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right). Therefore, the multiplication operation should be completed first, making 5 * 3 equal to 15, and then the addition operation should be conducted to get the final result of 8 + 15, which equals 23. Choices B, C, and D are incorrect because in this expression, multiplication takes precedence over addition, division, and subtraction according to the order of operations.

Correct Answer: A

Rationale: To divide 52 by 27 and 51 by 27, you get 52/27 and 51/27, respectively. When simplified, 52/27 is the correct answer. The other choices, 51/27, 52/29, and 51/29, are incorrect because they do not reflect the correct result of dividing the given numbers.