It is currently 22 Sep 2017, 06:53

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# MBA .com Prac test one some nuts, i couldnt crack

Author Message
Manager
Joined: 24 Mar 2010
Posts: 78

Kudos [?]: 15 [0], given: 9

Location: Mumbai, India
WE 1: 3
WE 2: 2
WE 3: 2
MBA .com Prac test one some nuts, i couldnt crack [#permalink]

### Show Tags

19 Apr 2010, 11:53
00:00

Difficulty:

(N/A)

Question Stats:

100% (00:26) correct 0% (00:00) wrong based on 1 sessions

### HideShow timer Statistics

A ) 5^21 *4^11= 10^n * 2 : find hte value of n

choices : 11, 21, 22, 32, 23. how to find??
_________________

ASHISH DONGRE
BE KIND & GENEROUS TO SHARE THE KUDOS...THE MORE YOUR GIVE THE MORE YOU GET

Kudos [?]: 15 [0], given: 9

Manager
Joined: 20 Feb 2009
Posts: 75

Kudos [?]: 43 [0], given: 0

Location: chennai
Re: MBA .com Prac test one some nuts, i couldnt crack [#permalink]

### Show Tags

19 Apr 2010, 12:34
5^21 * 4^11 = 10^n * 2

10^n * 2 = 5^21 * 4^11
=(5^11 * 4^11 ) * 5^10
= (5 * 4 )^11 * 5^10
= (20)^11 * 5^10
= 2^11 * 10^11 * 5^10
= 2* ( 5*2)^10 * 10^11
= 2* 10^20
n = 20

Kudos [?]: 43 [0], given: 0

Intern
Joined: 07 Apr 2010
Posts: 25

Kudos [?]: 14 [0], given: 6

Re: MBA .com Prac test one some nuts, i couldnt crack [#permalink]

### Show Tags

19 Apr 2010, 22:38
RHS: 10^n * 2 = 5^n * 2 ^n * 2
LHS: 5^21 * 4^11 = 5^21 * 2^22 = 5^21 * 2^21 * 2

compare both & u get n = 21
_________________

GMAT, here i come...

impressed?...how bout encouraging me with a kudos

cheers
just another idiot!

Kudos [?]: 14 [0], given: 6

Intern
Joined: 08 Apr 2010
Posts: 28

Kudos [?]: 12 [0], given: 3

Re: MBA .com Prac test one some nuts, i couldnt crack [#permalink]

### Show Tags

19 Apr 2010, 23:50
meghash3 wrote:
A ) 5^21 *4^11= 10^n * 2 : find hte value of n

choices : 11, 21, 22, 32, 23. how to find??

this can be done as under.
$$5^{21} *4^{11}= 10^n * 2$$
$$5^{21} *(2^2)^{11} = 2^n * 5^n * 2$$
$$2^{22} * 5^{21} = 2^{n+1} * 5^n$$
comparing both sides for the powers of 2 or 5, we see that n+1 = 22 and n = 21
_________________

CHEERS
fivezero7

Kudos [?]: 12 [0], given: 3

Re: MBA .com Prac test one some nuts, i couldnt crack   [#permalink] 19 Apr 2010, 23:50
Display posts from previous: Sort by

# MBA .com Prac test one some nuts, i couldnt crack

 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®.