Data Sufficiency

BTGmoderatorDC wrote:i) x - 4 = z
ii) y - x = 8
iii) 8 - z = t

For the system of equations given, what is the value of z?

(1) x = 7
(2) t = 5

Target question: What is the value of z?

Statement 1: x = 7
Scanning the three given equations, we see that equation i is all we need to determine the value of z
i) x - 4 = z
Replace x with 7 to get: 7 - 4 = z
So, z = 3
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: t = 5
Scanning the three given equations, we see that equation iii is all we need to determine the value of z
iii) 8 - z = t
Replace t with 5 to get: 8 - z = 5
So, z = 3
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent