It is currently 21 Oct 2017, 12:48

### 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

# If 5^2^1 X 4^1^1 = 2 X 10^n what is the value of n?

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Intern
Joined: 09 Jan 2009
Posts: 7

Kudos [?]: 7 [0], given: 0

If 5^2^1 X 4^1^1 = 2 X 10^n what is the value of n? [#permalink]

### Show Tags

09 Jan 2009, 09:40
1
This post was
BOOKMARKED
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If $$5^2^1 X 4^1^1 = 2 X 10^n$$ what is the value of n?

o 11
o 21
o 22
o 23
o 32

Hi, has someone a quick way of getting this done?

Answer A is correct (not E as indicated).

many Thx
Attachments

Picture 9.png [ 10.33 KiB | Viewed 1592 times ]

Kudos [?]: 7 [0], given: 0

Manager
Joined: 04 Jan 2009
Posts: 237

Kudos [?]: 13 [0], given: 0

Re: GMAT Prep - Exponent Problem [#permalink]

### Show Tags

09 Jan 2009, 09:48
I may be wrong; now I get B.

5^21x4^11 = 5^21x2^21x2=2x(5x2)^21
_________________

-----------------------
tusharvk

Kudos [?]: 13 [0], given: 0

Intern
Joined: 09 Jan 2009
Posts: 7

Kudos [?]: 7 [0], given: 0

Re: GMAT Prep - Exponent Problem [#permalink]

### Show Tags

09 Jan 2009, 09:57
sorry it is B

Kudos [?]: 7 [0], given: 0

Intern
Joined: 09 Jan 2009
Posts: 7

Kudos [?]: 7 [0], given: 0

Re: GMAT Prep - Exponent Problem [#permalink]

### Show Tags

09 Jan 2009, 10:06
thanks so far....but can you expalain your step from
4^11 to 2^21x2 ?

many thanks

Kudos [?]: 7 [0], given: 0

Manager
Joined: 04 Jan 2009
Posts: 237

Kudos [?]: 13 [0], given: 0

Re: GMAT Prep - Exponent Problem [#permalink]

### Show Tags

09 Jan 2009, 11:24
Oh I apologize; in my excitement I just jumped off.
5^21x4^11 = 5^21x(2^2)^11 = 5^21x2^22 = 2x2^21x5^21=2x(5x2)^21=2x10^21.

best.
_________________

-----------------------
tusharvk

Kudos [?]: 13 [0], given: 0

Senior Manager
Joined: 02 Nov 2008
Posts: 276

Kudos [?]: 117 [1], given: 2

Re: GMAT Prep - Exponent Problem [#permalink]

### Show Tags

09 Jan 2009, 13:46
1
KUDOS
tusharvk wrote:
Oh I apologize; in my excitement I just jumped off.
5^21x4^11 = 5^21x(2^2)^11 = 5^21x2^22 = 2x2^21x5^21=2x(5x2)^21=2x10^21.

best.

2 = 2^1
10^N = 2^N X 5^N

2 X 10^N = 2^(N+1) X 5^N

4^11 = 2^11 X 2^11
SO:
5^21 X 2^22 = 2^(N+1) X 5^N

Drop the bases and the answer is clearly 21.

Kudos [?]: 117 [1], given: 2

Manager
Joined: 01 Nov 2008
Posts: 127

Kudos [?]: 4 [0], given: 0

Re: GMAT Prep - Exponent Problem [#permalink]

### Show Tags

15 Jan 2009, 04:49
Yeah the Answer is B

Kudos [?]: 4 [0], given: 0

Re: GMAT Prep - Exponent Problem   [#permalink] 15 Jan 2009, 04:49
Display posts from previous: Sort by

# If 5^2^1 X 4^1^1 = 2 X 10^n what is the value of n?

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.