Correct Answer: B

Rationale: The formula to calculate the perimeter of a square is P = 4s, where P is the perimeter and s is the length of a side. Given that the side length is 5 meters, the perimeter is 4 * 5 = 20 meters. Therefore, the correct answer is B. Choices A (15 meters), C (25 meters), and D (30 meters) are incorrect as they do not correctly apply the formula to calculate the perimeter of a square.

Correct Answer: A

Rationale: To solve for x in the equation x/250 = 3/500, you can cross-multiply: x*500 = 3*250. Therefore, 500x = 750. Now, divide both sides by 500: x = 750/500. Simplifying, x = 1.5. Therefore, the correct answer is A, 1.5. Choice B, 25.5, is incorrect as it does not match the correct calculation. Choice C, 1500, is incorrect as it is not the result of solving the equation given. Choice D, 2.5, is incorrect as well, as it does not align with the correct value of x obtained from the equation.

Correct Answer: A

Rationale: To add mixed numbers, first convert them to improper fractions. 6 3/4 = 27/4 and 8 1/6 = 49/6. Finding a common denominator, we get 27/4 + 49/6 = 81/12 + 98/12 = 179/12 = 14 & 11/12. Therefore, the correct answer is A. Choice B is incorrect as it does not simplify to the correct result. Choice C is in fraction form and not in mixed number form, making it incorrect. Choice D is not the correct sum of the given mixed numbers, so it is also incorrect.

Correct Answer: D

Rationale: To determine the highest number among 0.077, 0.777, 0.08, and 0.87, we compare the numbers. 0.87 is greater than 0.777, 0.08, and 0.077, making it the highest number. Choice A (0.077), Choice B (0.777), and Choice C (0.08) are lower numbers compared to 0.87, so they are incorrect.

Correct Answer: B

Rationale: To calculate the profit, first determine the total revenue: 7 stands * 11 paintings per stand * $5.50 per painting = $423.50. Then, subtract the total stand expenses ($35 per stand * 7 stands = $245) from the total revenue to get the profit: $423.50 - $245 = $178.50. Therefore, the correct answer is $178.50. Option A is incorrect because it does not account for the stand expenses. Option C is incorrect as it does not consider the total revenue. Option D is incorrect as it overestimates the profit by not deducting the stand expenses.