Answer: B. $16000$ Explanation: 1) Set the two equations equal to each other: $3x + 5000 = -3x + 11000$. 2) Combine like terms: $6x = 6000 \Rightarrow x = 1000$. 3) Substitute into one equation, e.g., $y = 3(1000) + 5000 = 8000$. 4) Therefore, $2y = 2(8000) = 16000$. Common mistake: Some students may forget to multiply by 2 at the end, stopping at $y = 8000$.