Find all School-related info fast with the new School-Specific MBA Forum
Learn more about the recent changes... close

It is currently 25 May 2013, 20:43
Customize  |  Hide

Search
Register
New posts
Unanswered

Exponent problem

  Question banks Downloads My Bookmarks Reviews  
  Oldest Best Reply
Search for:
 
Print view
First unread post
Author Message
TAGS:
Intern
Intern
Joined: 09 Jan 2007
Posts: 26
Followers: 0

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

Exponent problem [#permalink] New post 06 Feb 2007, 17:21
If 5^21X4^11=2X10^n, what is n?

11
21
22
23
32


The answer is 21, but why? Step by step please. Thank you.
Manager
Manager
User avatar
Joined: 22 Feb 2004
Posts: 60
Location: Florida
Followers: 1

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

 [#permalink] New post 06 Feb 2007, 17:54
I'm no math expert, but here is how I did it.

The first thing I did was rename 4^21 as 2^22. This is because 4=2^2 and you multiply the exponents.

The second step was to divide both sides by 2, to get 5^21 * 2^21 = 10^n

When I saw this I realized that what you're saying is you have 21 groups of 5 and 21 groups of 2. Since 5 * 2=10, you have 21 groups of 10 or 10^21.

I don't know if there is an exponent rule for the last step, but that's how I solved it.
Intern
Intern
Joined: 09 Jan 2007
Posts: 26
Followers: 0

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

 [#permalink] New post 06 Feb 2007, 18:47
Thanks for the explanation
SVP
SVP
User avatar
Joined: 05 Jul 2006
Posts: 1568
Followers: 4

Kudos [?]: 63 [0], given: 36

CAT Tests
 [#permalink] New post 07 Feb 2007, 01:59
If 5^21X4^11=2X10^n, what is n?

11
21
22
23
32

5^21 * 2^22 -1 = 2^n*5*n

thus 2^21 = 2^n , n = 21
  [#permalink] 07 Feb 2007, 01:59
    Similar topics Author Replies Last post
Similar
Topics:
 New posts Easy Exponent Problem Titleist 2 26 Nov 2003, 09:23
New posts Basic Exponent Problem Roc-a-fella 3 17 Aug 2004, 09:50
New posts exponent problem ej20 3 23 Mar 2006, 20:43
New posts Exponent Problem (simple) above720 3 02 Jan 2007, 22:31
Moved topic 8 Exponents Problem (m04q20) trahul4 18 19 Jun 2007, 20:15
Display posts from previous: Sort by

Exponent problem

  Question banks Downloads My Bookmarks Reviews  
Print view
First unread post

Moderators: Bunuel, VeritasPrepKarishma

Search for:


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®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com