Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Nov 2007:30 AM PST
-08:30 AM PST
Learn what truly sets the UC Riverside MBA apart and how it helps in your professional growth
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2510:00 AM EST
-11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.
19 Jan 2020, 23:10
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
95%
(hard)
Question Stats:
45% (02:36) correct
55%
(02:31)
wrong
based on 159
sessions
History
Date
Time
Result
Not Attempted Yet
If a and n are positive numbers, does \(2a^{2x}=n?\)
(1) \(a^x+\frac{1}{a^x}=\sqrt{n+2}\)
(2) \(x > 0\)
Are You Up For the Challenge: 700 Level Questions
Updated on: 20 Jan 2020, 23:35
Originally posted by CareerGeek on 20 Jan 2020, 04:15.
Last edited by CareerGeek on 20 Jan 2020, 23:35, edited 1 time in total.
Last edited by CareerGeek on 20 Jan 2020, 23:35, edited 1 time in total.
Kudos
Bookmarks
(1) \(a^x+\frac{1}{a^x} = \sqrt{n+2}\)
Squaring on both sides,
--> \((a^x+\frac{1}{a^x})^2 = n+2\)
--> \(a^{2x} + 2*a^x*\frac{1}{a^x} + \frac{1}{a^{2x}} = n + 2\)
--> \(a^{2x} + 2 + \frac{1}{a^{2x}} = n + 2\)
--> \(a^{2x} + \frac{1}{a^{2x}} = n\)
Does \(2a^{2x} = n\) ?
--> \(a^{2x} + \frac{1}{a^{2x}} = 2a^{2x}\)
--> \(a^{2x} = \frac{1}{a^{2x}}\)
--> \(a^{4x} = 1\)
Only Possible if \(x = 0\)
But we DO NOT know the value of x --> Insufficient
(2) \(x > 0\)
Does not talk anything about a & n --> Insufficient
Combining (1) & (2),
If \(x > 0\), \(a^{4x}\) is equal to 1 when a = 1
And not equal to 1 when a is not equal to 1
Insufficient
Option E
Squaring on both sides,
--> \((a^x+\frac{1}{a^x})^2 = n+2\)
--> \(a^{2x} + 2*a^x*\frac{1}{a^x} + \frac{1}{a^{2x}} = n + 2\)
--> \(a^{2x} + 2 + \frac{1}{a^{2x}} = n + 2\)
--> \(a^{2x} + \frac{1}{a^{2x}} = n\)
Does \(2a^{2x} = n\) ?
--> \(a^{2x} + \frac{1}{a^{2x}} = 2a^{2x}\)
--> \(a^{2x} = \frac{1}{a^{2x}}\)
--> \(a^{4x} = 1\)
Only Possible if \(x = 0\)
But we DO NOT know the value of x --> Insufficient
(2) \(x > 0\)
Does not talk anything about a & n --> Insufficient
Combining (1) & (2),
If \(x > 0\), \(a^{4x}\) is equal to 1 when a = 1
And not equal to 1 when a is not equal to 1
Insufficient
Option E
20 Jan 2020, 05:26
Kudos
Bookmarks
#1
a^x+1/a^x=√n+2
possible when
a=x=1 and n=2
we get yes sufficient
#2
x>0
a and n relation not know
insufficient
IMO A
a^x+1/a^x=√n+2
possible when
a=x=1 and n=2
we get yes sufficient
#2
x>0
a and n relation not know
insufficient
IMO A
