Correct Answer: B

Rationale: To estimate the total number of pounds of potatoes on the farmer's trailer, we can use the average weight of a bag of potatoes. The average weight is calculated by adding the minimum and maximum weights of the bags and dividing by 2: (23 + 27) / 2 = 25 pounds. Next, multiply the average weight by the total number of bags: 25 pounds/bag * 150 bags = 3,750 pounds. Therefore, the best estimate of the total number of pounds of potatoes on the farmer's trailer is 3,750 pounds. Choice A (3,000 pounds) is too low as it underestimates the total weight. Choice C (4,100 pounds) and Choice D (5,000 pounds) are too high as they overestimate the total weight.

Correct Answer: A

Rationale: The distance traveled by the bike in one complete roll of the tire is equal to the circumference, which can be calculated using the formula C = πd, where d is the diameter. Given that the diameter of the bike tire is 27 inches, the circumference is obtained by multiplying the diameter by π. As the tire rolls from the first mark to the fourth mark, it completes three full rotations (one complete roll plus two more). Therefore, the total distance rolled is 3 times the circumference, which results in 3(27π). Choice A is correct. Choice B is incorrect as it incorrectly multiplies the diameter by 4π instead of multiplying the circumference by 4. Choices C and D are incorrect as they involve dividing the diameter by a number, which is not applicable in this context.

Correct Answer: A

Rationale: To calculate the total cost, first, multiply the number of days by the cost per day: 3 days x $50/day = $150. Then, multiply the number of miles driven by the cost per mile: 120 miles x $0.25 = $30. Finally, add the two amounts together: $150 (daily cost) + $30 (mileage cost) = $180. Therefore, the correct total cost is $180, which corresponds to choice A. The other choices are incorrect because they do not reflect the accurate calculation of $150 for the daily cost and $30 for the mileage cost.

Correct Answer: B

Rationale: To simplify the expression 0.0178 2.401, you multiply the two numbers to get the result. Therefore, 0.0178 2.401 = 0.0427378. Choice A (2.0358414), Choice C (0.2341695), and Choice D (0.348324) are incorrect as they do not represent the correct result of the multiplication operation.

Correct Answer: A

Rationale: A proportional relationship is one in which two quantities vary directly with each other. In choice A, the amount deposited per month is directly proportional to the initial deposit. The relationship can be represented as y = 125x + 150, where x is the number of months and y is the total amount in the account. Choices B and C involve additional fixed amounts or variable costs that do not maintain a constant ratio, making them non-proportional relationships. Choice D refers to a constant speed of driving, which is not a proportional relationship as it does not involve varying quantities that change in direct proportion.