OG2015 DS x-4=z

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OG2015 DS x-4=z

by lionsshare » Sat Sep 16, 2017 10:13 pm
x-4=z
y-x=8
8-z=t

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

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

OA: D

Hello. Anyone, please share the solution on how to solve this. Thanks.

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by Brent@GMATPrepNow » Sun Sep 17, 2017 7:14 am
lionsshare 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

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by Jeff@TargetTestPrep » Fri Aug 03, 2018 2:06 pm
lionsshare wrote:x-4=z
y-x=8
8-z=t

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

(1) x = 7
(2) t = 5
We are given 3 equations:

1) x - 4 = z
2) y - x = 8
3) 8 - z = t

We need to determine the value of z.

Statement One Alone:

x = 7

We see that we can substitute 7 for x in the first equation and then determine the value of z.

x - 4 = z
7 - 4 = z
3 = z

Statement one alone is sufficient to answer the question.

Statement Two Alone:
t = 5

We see that we can substitute 5 for t in equation 3 and then determine the value of z.
8 - z = t
8 - z = 5
3 = z

Statement two alone is sufficient to answer the question.

Answer: D

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Head of GMAT Instruction
[email protected]

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