Correct Answer: D

Rationale: The factors of 12 are numbers that divide evenly into 12 without leaving a remainder. The correct factors of 12 are 1, 2, 3, 4, 6, and 12. Choice A (12, 24, 36) is incorrect as only 12 is a factor of 12. Choice B (1, 2, 4, 6, 12) includes all the correct factors of 12. Choice C (12, 24, 36, 48) is incorrect as 24, 36, and 48 are not factors of 12.

Correct Answer: B

Rationale: The median represents the middle value in an ordered set of numbers. To find the median, the numbers need to be arranged in ascending order: {2, 3, 9, 12, 15}. Since the set has an odd number of elements, the median will be the middle value, which is 9 in this case. Choice A (3) and Choice D (15) are incorrect as they do not fall in the middle of the ordered set. Choice C (12) is also incorrect as it is not the middle value in this particular set.

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 range where n lies when n = 8, we consider numbers greater and lesser than 8. The range would be between 7 and 9, not 9 and 11 as stated in the original rationale. Option A (5 and 7) and Option D (3 and 5) are lower ranges, while Option C (9 and 11) exceeds the upper limit.

Correct Answer: A

Rationale: To convert a decimal to a fraction, place the decimal value over the place value of the last digit. In this case, 0.0523 can be expressed as 523/10000 since the last digit is in the ten-thousandths place. Choice A is correct. Choices B, C, and D are incorrect because they represent different decimal values and do not match the correct conversion of 0.0523.