Correct Answer: D

Rationale: To solve the equation 2x + 4 = x - 6, first, subtract x from both sides to get x + 4 = -6. Then, subtract 4 from both sides to isolate x, resulting in x = -10. Therefore, the correct answer is x = -10. Choice A is incorrect as it does not follow the correct steps of solving the equation. Choice B is incorrect as it is the result of combining x terms incorrectly. Choice C is incorrect as it is not the correct result of solving the equation step by step.

Correct Answer: A

Rationale: The correct equation to represent the amount of money Andy will have saved is y = 15 + 28x. This is because Andy has already saved $15 and plans to save an additional $28 per month. Therefore, the total amount he will have saved can be calculated by adding the initial $15 to the monthly savings of $28 (28x), resulting in y = 15 + 28x. Choices B, C, and D do not correctly account for the initial $15 that Andy has saved and therefore do not represent the total amount correctly.

Correct Answer: A

Rationale: To calculate the total monthly earnings, we first find the commission earned on $5,000 sales, which is 3% of $5,000 = $150. Adding this commission to the $2,000 base salary gives a total of $2,000 + $150 = $2,150. Therefore, the correct total monthly earnings are $2,500. Choice B ($2,150) is incorrect because it only includes the base salary and the commission but miscalculates the total. Choices C ($2,100) and D ($2,300) are also incorrect as they do not account for the correct calculation of the commission on sales.

Correct Answer: C

Rationale: To find out how many milliliters the child should receive, divide the total required dosage of 240 mg by the concentration of the medication, which is 80 mg per 0.8 mL. 240 mg · 80 mg/mL = 3 mL. Since each dose is 0.8 mL, the total dosage for the child would be 3 doses x 0.8 mL per dose = 2.4 mL. Therefore, the correct answer is 2.4 mL. Choice A (0.8 mL) is the concentration of the medication, not the total dose. Choices B (1.6 mL) and D (3.2 mL) are incorrect calculations that do not consider the concentration of the medication and the total required dosage correctly.

Correct Answer: D

Rationale: Joshua must answer more than 92 points' worth of questions. Since each question is worth 4 points, the inequality is 4x > 92. Choice A (4x < 30) is incorrect as it represents that Joshua must answer less than 30 questions correctly, not earning more than 92 points. Choice B (4x < 92) is incorrect as it signifies that Joshua must earn less than 92 points, which contradicts the requirement. Choice C (4x > 30) is incorrect as it implies that Joshua must answer more than 30 questions correctly, but the threshold is 92 points, not 30 points.