If x = 1 – 2y, what is z?

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If x = 1 – 2y, what is z?

by VJesus12 » Mon Apr 01, 2019 4:07 am

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If x = 1 - 2y, what is z?

(1) 5x + 10y + z = 5
(2) x = 17 + 2y

[spoiler]OA=A[/spoiler]

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by Brent@GMATPrepNow » Mon Apr 01, 2019 5:37 am

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VJesus12 wrote:If x = 1 - 2y, what is z?

(1) 5x + 10y + z = 5
(2) x = 17 + 2y
Target question: What is the value of z?

Given: x = 1 - 2y

Statement 1: 5x + 10y + z = 5
Replace x with 1 - 2y to get: 5(1 - 2y) + 10y + z = 5
Expand: 5 - 10y + 10y + z = 5
Simplify: 5 + z = 5
Solve: z = 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x = 17 + 2y
Replace x with 1 - 2y to get: 1 - 2y = 17 + 2y
Solve: y = -4
We still have no idea about the value of z
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

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