Find all School-related info fast with the new School-Specific MBA Forum

It is currently 29 Jun 2015, 15:27

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Root/ Exponents...easy way?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 14 Dec 2011
Posts: 65
GMAT 1: 630 Q48 V29
GMAT 2: 690 Q48 V37
Followers: 1

Kudos [?]: 14 [0], given: 24

Root/ Exponents...easy way? [#permalink] New post 29 Dec 2011, 21:31
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

67% (01:37) correct 33% (02:25) wrong based on 9 sessions
If (2^x)^y = (x^2)^z, the value of y when x is 16 and z is 32 is how much greater than the value of y when x and z are both 8 ?

6
10
16
17
24


My Idea

2^(x*y) = x^(2*z)
2^(16y) = 16^64 ---- > no idea how to get y out of this
2^(8y) = 8^16 ---- > and again no idea how to get y

How to I solve those equations?

Thanks a lot!
[Reveal] Spoiler: OA
Manager
Manager
avatar
Joined: 17 Oct 2011
Posts: 241
Location: United States
Concentration: Strategy, Marketing
GMAT 1: 720 Q51 V36
Followers: 4

Kudos [?]: 77 [0], given: 36

Re: Root/ Exponents...easy way? [#permalink] New post 29 Dec 2011, 22:14
Impenetrable wrote:
If (2^x)^y = (x^2)^z, the value of y when x is 16 and z is 32 is how much greater than the value of y when x and z are both 8 ?

6
10
16
17
24


My Idea

2^(x*y) = x^(2*z)
2^(16y) = 16^64 ---- > no idea how to get y out of this
2^(8y) = 8^16 ---- > and again no idea how to get y

How to I solve those equations?

Thanks a lot!


\(2^(xy)=x^(2z)\)
\(2^(16y)=16^64\)
but,\(16=2^4\)
so, \(2^(16y)=2^(4*64)\)
\(16y=4*64\)
\(y=16\)

similarly,
\(8=2^3\)
so, \(8y=3*2*8\)
or, \(y=6\)
Answer: B

Hope this helps.
Senior Manager
Senior Manager
avatar
Joined: 13 May 2011
Posts: 319
WE 1: IT 1 Yr
WE 2: Supply Chain 5 Yrs
Followers: 19

Kudos [?]: 161 [0], given: 11

Re: Root/ Exponents...easy way? [#permalink] New post 30 Dec 2011, 02:01
for the 1st condition: 2^16y=2^(16*16)
y=16
for the 2nd condition: 2^8y=2^(6*8)
y=6
16-6=10=B
Re: Root/ Exponents...easy way?   [#permalink] 30 Dec 2011, 02:01
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic Root(80)+root(125) Bunuel 11 01 Oct 2012, 04:02
1 root banksy 1 15 Mar 2011, 15:44
1 Roots rahulms 4 21 Jan 2010, 05:31
Roots TheRob 1 20 Aug 2009, 05:43
PS: Roots eastcoaster9 3 26 Sep 2005, 22:35
Display posts from previous: Sort by

Root/ Exponents...easy way?

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.