Correct Answer: C

Rationale: The correct answer is C: 8 pints. In the U.S. customary system, there are 8 pints in a gallon. This conversion is essential to know for various activities like cooking, measuring liquids, or understanding container volumes. Choice A, 2 pints, is incorrect as it represents half a gallon. Choice B, 4 pints, is incorrect as it represents a half-gallon or a quart. Choice D, 16 pints, is incorrect as it represents two gallons. Therefore, the correct answer is C, 8 pints.

Correct Answer: A

Rationale: The correct answer is A: PEMDAS. PEMDAS stands for the order of operations: Parentheses, Exponents, Multiplication and Division (left to right), Addition and Subtraction (left to right). It is a fundamental rule to follow in mathematics to ensure calculations are done correctly. Choices B, C, and D are incorrect as they do not encompass the essential rule that PEMDAS provides for solving mathematical expressions.

Correct Answer: C

Rationale: To find the percentage of the time Cora did not fall, subtract the number of times she fell (20) from the total number of times she skated around the rink (27). This gives us 27 - 20 = 7 times she did not fall. To express this as a percentage, calculate (7/27) * 100% = 25.93%, which is approximately 26%. Therefore, the correct answer is 0.26 (C). Choice A (0.37), Choice B (0.74), and Choice D (0.15) are incorrect as they do not represent the percentage of the time Cora did not fall based on the information provided.

Correct Answer: B

Rationale: The correct answer is B: 1,000 mm. This is because there are 1,000 millimeters in a meter. To convert from meters to millimeters, you need to multiply by 1,000. Choices A, C, and D are incorrect. A meter is equivalent to 1,000 millimeters, not 100 (A), 10,000 (C), or 100,000 (D) millimeters.

Correct Answer: A

Rationale: The correct formula to find the circumference of a circle is C = 2πr, where C represents the circumference and r is the radius of the circle. Choice B, Circumference = πr², represents the formula for the area of a circle rather than the circumference. Choice C, Circumference = 2r², is incorrect as it does not involve π in the formula. Choice D, Circumference = r²π, has the terms reversed compared to the correct formula; the formula should start with the constant (2) multiplied by π, followed by the radius.