Correct Answer: C

Rationale: To find the y-intercept, set x = 0 in the equation 7y − 42x + 7 = 0. This simplifies to 7y - 42(0) + 7 = 0, which gives 7y = -7. Solving for y, we get y = -1. Therefore, the y-intercept is where x = 0, so the correct answer is (0, -1). Choice A (1/6, 0) is incorrect as it does not satisfy the given equation when x = 0. Choice B (6, 0) is incorrect as it represents the x-intercept. Choice D (-1, 0) is incorrect as it does not correspond to the y-intercept of the given equation.

Correct Answer: C

Rationale: To calculate the total cost, convert all weights to kilograms. 800 grams = 0.8 kilograms; 300 grams = 0.3 kilograms. Add up the weights: 1.2 kg + 0.8 kg + 0.3 kg = 2.3 kg. Multiply the total weight by the cost per kilogram: 2.3 kg $4/kg = $9.20. Therefore, the total cost of her produce is $9.20. Choice A, $4.40, is incorrect as it does not account for the total weight of all the fruits. Choice B, $5.24, is incorrect as it does not accurately calculate the total cost based on the given weights and price per kilogram. Choice D, $48.80, is incorrect as it is significantly higher than the correct total cost and suggests an incorrect calculation method.

Correct Answer: C

Rationale: To determine the total cost before tax, calculate: 5 shirts $3/shirt + 4 pants $6/pair of pants + 2 items mended $5/item mended = $49. Now, multiply this amount by 1.08 to include the 8% sales tax: $49 1.08 = $52.92. Therefore, Annie's total bill will be $52.92. Choice A, $45.08, is incorrect as it does not include the correct calculation for the total bill. Choice B, $49.00, is wrong because it is the total cost before tax and does not consider the added sales tax. Choice D, $88.20, is incorrect as it does not accurately calculate the total bill including the sales tax.

Correct Answer: A

Rationale: Let s be the number of sandwiches sold. Each sandwich earns $4, so selling s sandwiches at $4 each results in revenue of $4s. Similarly, d drinks at $2 each give $2d of income, and cookies bring in $1c. Summing these values gives total revenue = 4s + 2d + 1c. Therefore, option A, r = 4s + 2d + 1c, correctly represents the shop's revenue. Choices B, C, and D are incorrect because they incorrectly multiply the prices of each item by more than one day's sales, which would overstate the total revenue for a three-day period.

Correct Answer: D

Rationale: To solve the equation 8x − 6 = 3x + 24, start by adding 6 to both sides: 8x − 6 + 6 = 3x + 24 + 6, which simplifies to 8x = 3x + 30. Next, subtract 3x from both sides to get 5x = 30. Finally, divide both sides by 5 to solve for x: x = 6. Therefore, the correct solution is x = 6. Choices A, B, and C are incorrect because they do not result from the correct algebraic manipulation of the equation.