For any integer n, denotes the product of all of the : PS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 18 Jan 2017, 09:30

# STARTING SOON:

Open Admission Chat with MBA Experts of Personal MBA Coach - Join Chat Room to Participate.

### 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

# For any integer n, denotes the product of all of the

Author Message
Manager
Joined: 07 Dec 2006
Posts: 168
Followers: 1

Kudos [?]: 76 [0], given: 0

For any integer n, denotes the product of all of the [#permalink]

### Show Tags

25 Jan 2008, 22:39
00:00

Difficulty:

(N/A)

Question Stats:

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

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

For any integer n, [n] denotes the product of all of the positive even numbers' from 2 to n. What is the largest prime factor of [23] + [21]?

A) 23
B) 19
C) 11
D) 7
E) 5

Do you have shortcut to solve this problem?

OA is A.
CEO
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 546

Kudos [?]: 3555 [0], given: 360

Re: PS - Product of all the positive even numbers [#permalink]

### Show Tags

25 Jan 2008, 23:51
A

[23] + [21] = [22] + [20] = [20]*(22+1) = 2*10!*23
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Senior Manager
Joined: 22 Sep 2005
Posts: 276
Followers: 1

Kudos [?]: 188 [0], given: 1

Re: PS - Product of all the positive even numbers [#permalink]

### Show Tags

26 Jan 2008, 08:44
It must be A (23), because the balance possible prime numbers are in both series.

A too!!!
Intern
Joined: 14 Sep 2007
Posts: 42
Followers: 1

Kudos [?]: 5 [0], given: 0

Re: PS - Product of all the positive even numbers [#permalink]

### Show Tags

26 Jan 2008, 15:54
i dont understand either explanation...

i could do the grunt math out but theres gotta bea faster way that im not seeing
SVP
Joined: 04 May 2006
Posts: 1926
Schools: CBS, Kellogg
Followers: 22

Kudos [?]: 1011 [0], given: 1

Re: PS - Product of all the positive even numbers [#permalink]

### Show Tags

26 Jan 2008, 17:54
GMAT4Lyfe wrote:
i dont understand either explanation...

i could do the grunt math out but theres gotta bea faster way that im not seeing

[23]=2*4*6*8*10*12*14*16*18*20*22
[21]=2*4*6*8*10*12*14*16*18*20

[23]+[21]=2*4*6*8*10*12*14*16*18*20*(22+1)
[23]+[21]=2*4*6*8*10*12*14*16*18*20*23
_________________
Re: PS - Product of all the positive even numbers   [#permalink] 26 Jan 2008, 17:54
Display posts from previous: Sort by