What is the value of xy - yz?

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What is the value of xy - yz?

by BTGmoderatorLU » Fri Aug 27, 2021 5:30 am

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Source: Official Guide

What is the value of xy - yz?

1) y = 2
2) x - z = 5

The OA is C

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Re: What is the value of xy - yz?

by Brent@GMATPrepNow » Sat Aug 28, 2021 6:41 am

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BTGmoderatorLU wrote:
Fri Aug 27, 2021 5:30 am
Source: Official Guide

What is the value of xy - yz?

1) y = 2
2) x - z = 5

The OA is C
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

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Brent
Brent Hanneson - Creator of GMATPrepNow.com
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