Correct Answer: A

Rationale: To compare, convert both to decimals or percentages: Sally ate 3/5, which is 0.6 or 60%. John ate 75%. Since 75% is greater than 60%, John ate more than Sally. Thus, the correct answer is A. John. Choice B is incorrect because Sally ate a smaller percentage of her lunch compared to John. Choice C is incorrect as the percentages consumed are different. Choice D is incorrect as one of them ate more.

Correct Answer: C

Rationale: To find the volume of the frustum of a cone, divide it into two cones and calculate their volumes separately. The formula for the volume of a cone frustum involves the radii of both bases and the height. The volume of the frustum cone can be calculated as V = 1/3 * π * h * (R^2 + r^2 + R * r), where R is the larger radius, r is the smaller radius, and h is the height. Substituting the values, V = 1/3 * π * 15 * (10^2 + 20*10 + 20^2) = 1875 cu cm. Therefore, the correct answer is 1875 cu cm. Choice A, B, and D are incorrect as they do not correspond to the correct calculation of the frustum's volume.

Correct Answer: A

Rationale: To determine the patient with the highest systolic pressure from the table, you should find the largest number in the 'systolic pressure' column. This method directly identifies the individual with the highest systolic pressure. Comparing the means (averages) of each age group, as suggested in choice B, may not pinpoint the specific patient with the highest systolic pressure, as averages can sometimes mask extreme values. Adding all systolic pressure values and dividing by the total number of patients, as in choice C, calculates the average systolic pressure for all patients, not identifying the highest individual reading. Subtracting the lowest systolic pressure from the highest, as in choice D, determines the range of systolic pressures but does not directly point out the patient with the highest reading.

Correct Answer: A

Rationale: To add mixed numbers, first convert the fractions to a common denominator. The least common denominator between 8 and 12 is 24. Converting 7 1/8 to 7 3/24 (since 1/8 = 3/24) and 2 4/12 to 2 8/24 (since 4/12 = 8/24), we can add the whole numbers separately to get 9. Then, adding the fractions 3/24 and 8/24 gives 11/24. Therefore, 7 1/8 + 2 4/12 equals 9 11/24. Choice A is correct. Choices B, C, and D are incorrect as they do not reflect the correct addition of mixed numbers with the appropriate conversion of fractions.

Correct Answer: A

Rationale: To convert centimeters to inches, divide the measurement in centimeters by 2.54 (since 1 inch = 2.54 cm). Therefore, 65.4 cm · 2.54 = 25.74 inches. This means that the model's waist measurement of 65.4 centimeters is equivalent to 25.74 inches. Choices B, C, and D are incorrect as they do not result from the correct conversion calculation.