BTGModeratorVI wrote: ↑Wed Oct 07, 2020 7:12 am
What is the value of xy - yz?
(1) y = 2
(2) x - z = 5
Answer:
C
Source: Official guide
Important: Notice that we can take xy - yz and factor out the y to get the following equivalent expression: y(x - z)
Target question: What is the value of y(x - z)?
Statement 1: y = 2
Our goal is to determine the value of
y(x - z)
We now know the value of y, but we don't know the value of (x - z)
Statement 1 is NOT SUFFICIENT
Statement 2: x - z = 5
Our goal is to determine the value of
y(x - z)
We now know the value of (x - z), but we don't know the value of y
Statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
Statement 1 tells us that y = 2
Statement 2 tells us that x - z = 5
So,
y(x - z) = 2(5) = 10
Since we can answer the
target question with certainty, the combined statements are SUFFICIENT
Answer: C
Cheers,
Brent
