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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## Does x = y? tagged by: Vincen ##### This topic has 2 expert replies and 0 member replies ### Top Member ## Does x = y? Does x = y? (1) 4x - 2y = 80 (2) x = (40 + y)/2 The OA is the option E. Using both equations, cannot find the correct answer? Experts, I would be thankful for your explanation. ### GMAT/MBA Expert Legendary Member Joined 14 Jan 2015 Posted: 2666 messages Followed by: 125 members Upvotes: 1153 GMAT Score: 770 Vincen wrote: Does x = y? (1) 4x - 2y = 80 (2) x = (40 + y)/2 The OA is the option E. Using both equations, cannot find the correct answer? Experts, I would be thankful for your explanation. The key is to recognize that the statements are identical: Statement 2: x = (40 + y)/2 Multiply both sides by 4: 4x = 2(40 + y) 4x = 80 + 2y 4x - 2y = 80 Clearly, neither statement alone is sufficient, so if the statements are identical, the answer must be E (If it doesn't feel intuitive that neither statement alone is sufficient, consider cases, If x = y, then we'd have 4x -2x =80 --> 2x = 80 --> x =. 40. So it could be the case that x = 40 and y = 40, giving us a YES. But it could also be the case that x = 20 and y = 0, giving us a NO.) _________________ Veritas Prep | GMAT Instructor Veritas Prep Reviews Save$100 off any live Veritas Prep GMAT Course

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### GMAT/MBA Expert

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Vincen wrote:
Does x = y?

(1) 4x - 2y = 80
(2) x = (40 + y)/2
We need to determine whether x = y.

Statement One Alone:

4x - 2y = 80

Simplifying the equation we have, 2x - y = 40; however, we cannot determine whether x = y. If we let x = 0 and y = -40, then we see that x is not equal to y. However, if we let x = 40/3 and y = 40/3, then x = y.

Statement Two Alone:

x = (40 + y)/2

Simplifying the equation, we have:

2x = 40 + y

2x - y = 40

Again, we cannot determine whether x = y.

Statements One and Two Together:

Using both statements together, we see that they produce the identical equations of 2x - y = 40; thus, we cannot determine whether x = y.

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scott@targettestprep.com

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