GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

It is currently 29 May 2020, 09:12

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.

Close

Request Expert Reply

Confirm Cancel

10! + 9! can be rewritten as:

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 64242
10! + 9! can be rewritten as:  [#permalink]

Show Tags

New post 25 Apr 2017, 01:16
11
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

63% (01:24) correct 37% (01:24) wrong based on 182 sessions

HideShow timer Statistics

Most Helpful Expert Reply
GMAT Club Legend
GMAT Club Legend
User avatar
V
Joined: 11 Sep 2015
Posts: 4878
Location: Canada
GMAT 1: 770 Q49 V46
Re: 10! + 9! can be rewritten as:  [#permalink]

Show Tags

New post 07 Mar 2018, 09:16
4
Top Contributor
1
Bunuel wrote:
10! + 9! can be rewritten as:

A. 9!(10)
B. 11!/10
C. (10!)^2*9
D. (9!)^2 + 10
E. 19!


First recognize that 10! = (10)(9!)
Here's why:
10! = (10)(9)(8)(7)(6)(5)(4)(3)(2)(1)
= (10)(9!)

So....
10! + 9! = (10)(9!) + 9!
= 9!(10 + 1) [I factored out the 9!]
= 9!(11)
Check the answer choice.....9!(11) isn't there! So, we'll need to check each answer choice to see which one can be expressed as (9!)(11)



A. 9!(10)
We can clearly see that this is not equal to (9!)(11)
ELIMINATE A


B. 11!/10
11!/10 = (11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)/(10)
= (11)(9)(8)(7)(6)(5)(4)(3)(2)(1)
= (11)(9!) PERFECT!!
= B

Cheers,
Brent
_________________
Test confidently with gmatprepnow.com
Image
General Discussion
Intern
Intern
avatar
B
Joined: 13 Sep 2015
Posts: 25
Re: 10! + 9! can be rewritten as:  [#permalink]

Show Tags

New post 25 Apr 2017, 01:27
1
10! + 9!
= (10*9!)+ 9!
=9! (10+1)
=9!(11)
=(9!*11*10)/10
=11!/10

Hence B

Sent from my D6502 using GMAT Club Forum mobile app
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2800
Re: 10! + 9! can be rewritten as:  [#permalink]

Show Tags

New post 12 Mar 2018, 09:55
Bunuel wrote:
10! + 9! can be rewritten as:

A. 9!(10)
B. 11!/10
C. (10!)^2*9
D. (9!)^2 + 10
E. 19!


10! + 9! = 10 x 9! + 9! = 9!(10 + 1) = 9!(11) = 11!/10

Answer: B
_________________

Jeffrey Miller

Head of GMAT Instruction

Jeff@TargetTestPrep.com
TTP - Target Test Prep Logo
214 Reviews

5-STAR RATED ONLINE GMAT QUANT SELF STUDY COURSE

NOW WITH GMAT VERBAL (PRE-BETA)

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15016
Re: 10! + 9! can be rewritten as:  [#permalink]

Show Tags

New post 09 Feb 2020, 06:34
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Club Bot
Re: 10! + 9! can be rewritten as:   [#permalink] 09 Feb 2020, 06:34

10! + 9! can be rewritten as:

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne