Correct Answer: A

Rationale: The correct way to find the least common multiple is to list all the multiples of each number and then identify the smallest common multiple. Choice A is correct because it describes the correct process. Listing factors, as suggested in choice B, helps in finding the greatest common factor, not the least common multiple. Dividing the largest number by the smallest, as mentioned in choice C, does not help find the least common multiple. Multiplying the two numbers together, as stated in choice D, results in their least common multiple when the numbers have no common factors.

Correct Answer: B

Rationale: To calculate the percentage increase, subtract the initial value from the final value, then divide by the initial value and multiply by 100. In this case, the calculation is ((1072 - 841) / 841) x 100 ≈ 27%. Therefore, the correct answer is B. Choice A (22%) is incorrect as it does not match the calculated percentage increase. Choice C (127%) is incorrect as it represents an absolute increase, not a percentage increase. Choice D (78%) is incorrect as it is not close to the calculated percentage increase of 27%.

Correct Answer: B

Rationale: To find the sale price after a 15% discount, you calculate 15% of $78, which is $11.70. Subtracting $11.70 from the original price gives $66.30. Since the price is typically rounded, the estimated sale price is $66. Choice A, $12, is too low and does not reflect a 15% discount off $78. Choice C, $22, and choice D, $69, are also incorrect as they do not accurately estimate the sale price after a 15% discount.

Correct Answer: A

Rationale: The correct way to find the least common multiple is to list all the multiples of each number and then identify the smallest common multiple. Choice A is correct because it describes the correct process. Listing factors, as suggested in choice B, helps in finding the greatest common factor, not the least common multiple. Dividing the largest number by the smallest, as mentioned in choice C, does not help find the least common multiple. Multiplying the two numbers together, as stated in choice D, results in their least common multiple when the numbers have no common factors.

Correct Answer: A

Rationale: The correct answer is A: 1000 mL. This is a standard conversion in the metric system where 1 liter is equivalent to 1000 milliliters. Choice B, 100 mL, is incorrect as it represents only a tenth of a liter. Choice C, 10 mL, is incorrect as it represents only a hundredth of a liter. Choice D, 1 mL, is significantly less than a liter, as it is only a thousandth of a liter.