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# u=?

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Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 5839
GMAT 1: 760 Q51 V42
GPA: 3.82

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25 Jul 2016, 19:40
00:00

Difficulty:

25% (medium)

Question Stats:

67% (00:29) correct 33% (00:47) wrong based on 149 sessions

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u=?
1) |u|+|v|=0
2) u^2+v^2=0

*An answer will be posted in 2 days

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MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
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"Only $99 for 3 month Online Course" "Free Resources-30 day online access & Diagnostic Test" "Unlimited Access to over 120 free video lessons - try it yourself" Manager Joined: 07 Jul 2016 Posts: 79 GPA: 4 u=? [#permalink] ### Show Tags 26 Jul 2016, 11:12 1 MathRevolution wrote: u=? $$\textbf{1) }\vert u \vert +\vert v\vert =0$$ The minimum result of the absolute value operator is 0. There is a single input for this: 0. $$u = v = 0$$ Sufficient $$\textbf{2) }u^2+v^2=0$$ The minimum result of squaring a number is 0 (barring complex numbers). There is a single input for this: 0. $$u = v = 0$$ Sufficient (D) each statement alone is sufficient Note that the answer would change if negative values could be obtained from either function. _________________ Please press +1 Kudos if this post helps. Senior Manager Joined: 20 Feb 2015 Posts: 421 Concentration: Strategy, General Management Re: u=? [#permalink] ### Show Tags 27 Jul 2016, 04:13 MathRevolution wrote: u=? 1) |u|+|v|=0 2) u^2+v^2=0 *An answer will be posted in 2 days 1) |u|+|v|=0 same as (+ve value) + ( +ve value) = 0 only possible when u and v are 0 therefore sufficient. 2) u^2+v^2=0 same as above +ve + +ve = 0 sufficient. D Current Student Joined: 18 Oct 2014 Posts: 880 Location: United States GMAT 1: 660 Q49 V31 GPA: 3.98 Re: u=? [#permalink] ### Show Tags 27 Jul 2016, 18:01 1 MathRevolution wrote: u=? 1) |u|+|v|=0 2) u^2+v^2=0 *An answer will be posted in 2 days 1) |u|+|v|=0 |u|=-|v| how can a positive value be equal to -ve value. Only when u=v=0 Sufficient. 2) u^2+v^2=0 u^2= -v^2 u^2 will always be +ve and it can not be equal to -ve value. Its possible only when u=v=0 Sufficient Both statements are sufficient independently. D is the answer _________________ I welcome critical analysis of my post!! That will help me reach 700+ CEO Joined: 12 Sep 2015 Posts: 2633 Location: Canada Re: u=? [#permalink] ### Show Tags 28 Jul 2016, 07:51 Top Contributor MathRevolution wrote: u = ? 1) |u| + |v| = 0 2) u² + v² = 0 Target question: What is the value of u? Statement 1: |u| + |v| = 0 IMPORTANT: |k| is always greater than or equal to 0 So, |u| = some number greater than or equal to 0 AND |v| = some number greater than or equal to 0 So, statement 1 basically says: (some number greater than or equal to 0) + (some number greater than or equal to 0) = 0 This is possible ONLY IF each value is equal to zero. So, |v| = 0 and |u| = 0, which means u = 0 Since we can answer the target question with certainty, statement 1 is SUFFICIENT Statement 2: u² + v² = 0 IMPORTANT: k² is always greater than or equal to 0 So, u² = some number greater than or equal to 0 AND v² = some number greater than or equal to 0 So, statement 2 basically says: (some number greater than or equal to 0) + (some number greater than or equal to 0) = 0 This is possible ONLY IF each value is equal to zero. So, v² = 0 and u² = 0, which means u = 0 Since we can answer the target question with certainty, statement 2 is SUFFICIENT Answer = RELATED VIDEOS _________________ Brent Hanneson – Founder of gmatprepnow.com Math Revolution GMAT Instructor Joined: 16 Aug 2015 Posts: 5839 GMAT 1: 760 Q51 V42 GPA: 3.82 Re: u=? [#permalink] ### Show Tags 31 Jul 2016, 08:46 There are 2 variables in the original condition and there is a high chance that C is the correct answer. Using con 1) and con 2), we get u=v=0. Hence the correct answer is D. _________________ MathRevolution: Finish GMAT Quant Section with 10 minutes to spare The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy. "Only$99 for 3 month Online Course"
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17 Aug 2017, 08:25
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Re: u=?   [#permalink] 17 Aug 2017, 08:25
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