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

It is currently 17 Dec 2014, 21:40

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

3^x - 3^x-1 = 162, x (x - 1) = ? For some reason I'm stumped

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
avatar
Joined: 10 Feb 2006
Posts: 664
Followers: 3

Kudos [?]: 87 [0], given: 0

3^x - 3^x-1 = 162, x (x - 1) = ? For some reason I'm stumped [#permalink] New post 09 Jul 2006, 11:16
3^x - 3^x-1 = 162, x (x - 1) = ?

For some reason I'm stumped on this one. Do we have an exponent rule when doing addition???

Thank!!
_________________

GMAT the final frontie!!!.

Intern
Intern
avatar
Joined: 03 Jan 2006
Posts: 25
Followers: 0

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

Re: Exponents! [#permalink] New post 09 Jul 2006, 11:23
alimad wrote:
3^x - 3^x-1 = 162, x (x - 1) = ?

For some reason I'm stumped on this one. Do we have an exponent rule when doing addition???

Thank!!



3^x - 3^(x-1) = 162
=> {3^(x-1)} * {3-1} = 162 (Taking 3^(x-1) term common)
=> 3^(x-1) = 162/2
=> 3^(x-1) = 81
=> 3^(x-1) = 3^4
=> x-1 = 4
=> x=5

Last edited by shahsac on 09 Jul 2006, 11:41, edited 2 times in total.
Manager
Manager
User avatar
Joined: 16 Apr 2006
Posts: 79
Followers: 1

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

Re: Exponents! [#permalink] New post 09 Jul 2006, 11:24
alimad wrote:
3^x - 3^x-1 = 162, x (x - 1) = ?

For some reason I'm stumped on this one. Do we have an exponent rule when doing addition???

Thank!!


3^x[1-1/3]=162
3^x[2/3]=162
3^x=243
x=5
x(x-1)=20
Director
Director
avatar
Joined: 10 Feb 2006
Posts: 664
Followers: 3

Kudos [?]: 87 [0], given: 0

 [#permalink] New post 09 Jul 2006, 11:39
skandhadarshan, how were you able to get the common of 1/3 ???
_________________

GMAT the final frontie!!!.

Intern
Intern
avatar
Joined: 03 Jan 2006
Posts: 25
Followers: 0

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

 [#permalink] New post 09 Jul 2006, 11:44
alimad wrote:
skandhadarshan, how were you able to get the common of 1/3 ???



Because he took 3^x as common term

3^(x-1) can also be written as {(3^x)/3}
So when 3^x is taken out as a common term....1/3 is left behind.......
Director
Director
avatar
Joined: 10 Feb 2006
Posts: 664
Followers: 3

Kudos [?]: 87 [0], given: 0

 [#permalink] New post 09 Jul 2006, 12:10
gotcha!! Thank you gentleman.
_________________

GMAT the final frontie!!!.

  [#permalink] 09 Jul 2006, 12:10
    Similar topics Author Replies Last post
Similar
Topics:
11 Experts publish their posts in the topic Is (4^x)^(5-3x) = 1 ? kp1811 9 12 Nov 2009, 11:03
1 If 3 x - 3 x-1 = 162 , then x(x-1)= stinger 2 23 Apr 2008, 04:11
If (3)^x - (3)^x-1 = 162, then x(x-1) =? a)12 b)16 c)20 d)30 GMAT_700 3 21 Apr 2007, 14:33
3^x - 3^x-1 = 162, what is x(x-1)? Ans: 20 shehreenquayyum 4 15 Jul 2006, 17:45
If 3^x - 3^(x-1) = 162, then x(x-1)= a. 12 b. 16 c. 20 d. 30 jlui4477 8 19 Apr 2006, 20:47
Display posts from previous: Sort by

3^x - 3^x-1 = 162, x (x - 1) = ? For some reason I'm stumped

  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®.