GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 17 Jul 2018, 06:51

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# What is the value of x? 1) x^-4x=1 2) x^-x=1

Author Message
TAGS:

### Hide Tags

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 5839
GMAT 1: 760 Q51 V42
GPA: 3.82
What is the value of x? 1) x^-4x=1 2) x^-x=1 [#permalink]

### Show Tags

29 Sep 2017, 01:26
00:00

Difficulty:

65% (hard)

Question Stats:

45% (00:34) correct 55% (00:48) wrong based on 33 sessions

### HideShow timer Statistics

[GMAT math practice question]

What is the value of x?

1) $$x^{-4x}$$=1
2) $$x^{-x}$$=1

_________________

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" "Free Resources-30 day online access & Diagnostic Test" "Unlimited Access to over 120 free video lessons - try it yourself" PS Forum Moderator Joined: 25 Feb 2013 Posts: 1182 Location: India GPA: 3.82 What is the value of x? 1) x^-4x=1 2) x^-x=1 [#permalink] ### Show Tags Updated on: 01 Oct 2017, 20:13 MathRevolution wrote: [GMAT math practice question] What is the value of x? 1) $$x^{-4x}$$=1 2) $$x^{-x}$$=1 Statement 1: there are two possible values of $$x$$, $$x=1$$ or $$x=-1$$. Hence insufficient Statement 2: implies that $$x^{-x}=1$$, only one possible solution $$x=1$$. Hence sufficient Option B Originally posted by niks18 on 29 Sep 2017, 04:56. Last edited by niks18 on 01 Oct 2017, 20:13, edited 1 time in total. Math Revolution GMAT Instructor Joined: 16 Aug 2015 Posts: 5839 GMAT 1: 760 Q51 V42 GPA: 3.82 Re: What is the value of x? 1) x^-4x=1 2) x^-x=1 [#permalink] ### Show Tags 01 Oct 2017, 18:19 => Forget conventional ways of solving math questions. In DS, VA (Variable Approach) method is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution. In the original condition, there is 1 variable(x), which should match with the number of equations. So you need 1 equation. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer. Condition 1) We have 2 possible values, which are x = 1 and x = -1. This is not sufficient. Condition 2) The only possible value is x = 1. Therefore, the answer is B unlike our expectation. For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E. Answer: B _________________ 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"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Re: What is the value of x? 1) x^-4x=1 2) x^-x=1   [#permalink] 01 Oct 2017, 18:19
Display posts from previous: Sort by

# Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.