LUANDATO wrote:What is the value of (u + v)?

(1) 2w − 7 = 0
(2) u + v − 3w = 11

Target question: What is the value of (u + v)?

Statement 1: 2w − 7 = 0
No information about u or v.
Statement 1 is NOT SUFFICIENT

Statement 2: u + v − 3w = 11
There are several values of u, v and w and y that satisfy the equation u + v − 3w = 11. Here are two:
Case a:u = 14, v = 0 and w = 1. In this case, the answer to the target question is u + v = 14 + 0 = 14
Case b: u = 17, v = 0 and w = 2. In this case, the answer to the target question is u + v = 17 + 0 = 17
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
Statement 1 tells us that 2w − 7 = 0
Statement 2 tells us that u + v − 3w = 11

If we take 2w − 7 = 0 and solve for w, we get w = 3.5
Now take u + v − 3w = 11 and replace w with 3.5 to get: u + v − 3(3.5) = 11
Evaluate to get: u + v − 10.5 = 11
Add 10.5 to both sides to get: u + v = 21.5
So, the answer to the target question is u + v = 21.5
Since we can answer the target question with certainty, the combined statements are SUFFICIENT

Answer: C

Cheers,
Brent