What is the value of xy  yz?
(1) y = 2
(2) x  z = 5
Answer: C
Source: Official guide
What is the value of xy  yz?
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Important: Notice that we can take xy  yz and factor out the y to get the following equivalent expression: y(x  z)BTGModeratorVI wrote: ↑Wed Oct 07, 2020 7:12 amWhat is the value of xy  yz?
(1) y = 2
(2) x  z = 5
Answer: C
Source: Official guide
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
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To find the target question (i.e the value of xy  yz), we have to evaluate both statements' conditions.
Statement 1: y=2
There is no given value for x and z; this implies that we cannot estimate the value for xyyz. So, therefore, statement 1 is NOT SUFFICIENT.
Statement 2: xz=5
There is no given value for y; this implies that we cannot estimate the value for xyyz. So, therefore, statement 2 is NOT SUFFICIENT.
Combining both statements:
From statement 1, y=2
From statement 2, xz=5
xy  yz
y (xz) = 2(5) = 10
Since this combination of both statements answers the target question, then it is SUFFICIENT.
The answer is, therefore, option C.
Statement 1: y=2
There is no given value for x and z; this implies that we cannot estimate the value for xyyz. So, therefore, statement 1 is NOT SUFFICIENT.
Statement 2: xz=5
There is no given value for y; this implies that we cannot estimate the value for xyyz. So, therefore, statement 2 is NOT SUFFICIENT.
Combining both statements:
From statement 1, y=2
From statement 2, xz=5
xy  yz
y (xz) = 2(5) = 10
Since this combination of both statements answers the target question, then it is SUFFICIENT.
The answer is, therefore, option C.