Correct Answer: B

Rationale: To convert miles to kilometers, we use the conversion factor of 1 mile ≈ 1.60934 km. Therefore, 4.67 miles * 1.60934 km/mile = 7.514 km. When rounded to three significant digits, the answer is 7.51 km. Choice A of 7.514 km is the correct conversion, but the question asked for the answer to be rounded to three significant digits, making choice B, 7.51 km, the most precise and correct option. Choices C and D are incorrect conversions and do not match the correct conversion of 4.67 miles to kilometers.

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 find out how much paint Shawna uses on the first day, calculate 2/5 * 5 = 2 gallons. Subtracting the amount used from the total amount gives us 5 - 2 = 3 gallons remaining. Therefore, Shawna has 3 gallons of paint left after using 2 gallons on the first day. Choice A is correct. Choices B, C, and D are incorrect because she has more paint left than the options presented.

Correct Answer: D

Rationale: To find the perimeter of a rectangle, you add the lengths of all its sides. In this case, the formula for the perimeter of a rectangle is 2*(length + width). Substituting the given values, we get: 2*(7 cm + 3 cm) = 2*(10 cm) = 20 cm. Therefore, the correct answer is 20 cm. Choice A (21 cm) is incorrect because it is the sum of the individual sides rather than the perimeter. Choice B (10 cm) is incorrect because it only represents one side of the rectangle. Choice C (14 cm) is incorrect as it is not the total perimeter of the rectangle.

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.