Correct Answer: C

Rationale: To find the approximate percentage of the times Cora did not slip and fall, subtract the times she fell (20) from the total times around the rink (27), which gives 7. Then, divide the number of times she did not slip and fall (7) by the total times around the rink (27) and multiply by 100 to get the percentage. So, 7 divided by 27 equals 0.259, which rounds to approximately 26%. Therefore, the correct answer is 26%. Choice A (37%) is incorrect because it does not reflect the calculation based on the given information. Choice B (74%) is incorrect as it is not the result of the correct calculation. Choice D (15%) is incorrect as it does not match the calculated percentage based on the scenario provided.

Correct Answer: C

Rationale: To find how many hairs were used for the drug test, you need to calculate 1/7 of 100. 1/7 of 100 is 14.2857, which rounds to 14.29 when rounded to the nearest hundredth. Therefore, 14.29 hairs were used for the drug test. Choice A is incorrect as it does not account for rounding to the nearest hundredth. Choices B and D are incorrect as they do not accurately reflect the calculated value after rounding.

Correct Answer: C

Rationale: The prefix 'centi-' means one-hundredth. In the metric system, 1 meter is equal to 100 centimeters. Therefore, to convert meters to centimeters, you multiply the number of meters by 100. In this case, 7 meters is equal to 7 * 100 = 700 centimeters. Choice A is incorrect as it does not consider the conversion factor properly. Choice B is incorrect as it only accounts for a factor of 10 instead of 100. Choice D is incorrect as it overestimates the conversion by a factor of 10.

Correct Answer: D

Rationale: To solve the equation for x, follow these steps: 2x - 7 = 3. Add 7 to both sides to isolate 2x, resulting in 2x = 10. Then, divide by 2 on both sides to find x, which gives x = 5. Therefore, the correct answer is x = 5. Choices A, B, and C are incorrect because they do not accurately solve the equation.

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.