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

 It is currently 29 Jan 2020, 04:16

### 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

# How many different arrangements are possible to place seven different

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 60772
How many different arrangements are possible to place seven different  [#permalink]

### Show Tags

07 Nov 2019, 01:49
00:00

Difficulty:

45% (medium)

Question Stats:

64% (01:17) correct 36% (01:20) wrong based on 87 sessions

### HideShow timer Statistics

How many different arrangements are possible to place seven different books on a shelf if all three math books must be placed next to each other?

A. 120
B. 148
C. 360
D. 540
E. 720

Are You Up For the Challenge: 700 Level Questions

_________________
Intern
Joined: 13 Dec 2017
Posts: 2
Re: How many different arrangements are possible to place seven different  [#permalink]

### Show Tags

07 Nov 2019, 02:00
Consider the math book as one group. Hence the total nos are remaing 4 books plus one group of math books

And is 5!

Posted from my mobile device
Senior Manager
Joined: 21 Jun 2017
Posts: 399
Location: India
Concentration: Finance, Economics
Schools: IIM
GMAT 1: 620 Q47 V30
GPA: 3
WE: Corporate Finance (Commercial Banking)
Re: How many different arrangements are possible to place seven different  [#permalink]

### Show Tags

07 Nov 2019, 02:12
Avakash wrote:
Consider the math book as one group. Hence the total nos are remaing 4 books plus one group of math books

And is 5!

Posted from my mobile device

Maths books are not identical, hence must by multiples by 3!
And E
GMAT Club Legend
Joined: 18 Aug 2017
Posts: 5752
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: How many different arrangements are possible to place seven different  [#permalink]

### Show Tags

07 Nov 2019, 09:48
Bunuel wrote:
How many different arrangements are possible to place seven different books on a shelf if all three math books must be placed next to each other?

A. 120
B. 148
C. 360
D. 540
E. 720

Are You Up For the Challenge: 700 Level Questions

all three books together = xxx*a*b*c*d ; 5! ways and xxx can be arranged in 3! ways
total ways ; 5!*3! = 720
IMO E
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 9167
Location: United States (CA)
Re: How many different arrangements are possible to place seven different  [#permalink]

### Show Tags

12 Nov 2019, 20:19
1
Bunuel wrote:
How many different arrangements are possible to place seven different books on a shelf if all three math books must be placed next to each other?

A. 120
B. 148
C. 360
D. 540
E. 720

Are You Up For the Challenge: 700 Level Questions

We must treat the 3 math books as a single entity, so one arrangement of the books is as shown here:

[M1-M2-M3]-B4-B5-B6-B7

Treating the 3 math books as a single entity, we see that we have 5! ways to arrange the books. However, the 3 math books can be arranged in 3! ways. Thus, the total number of ways to arrange the books is 5! x 3! = 120 x 6 = 720.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
181 Reviews

5-star rated online GMAT quant
self study course

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.

Manager
Joined: 27 Mar 2017
Posts: 119
Re: How many different arrangements are possible to place seven different  [#permalink]

### Show Tags

14 Nov 2019, 11:18
generis Bunuel

If the 3 math books were same, would we divide the answer by 3! ? Or the grouping i.e 4 + 1 would take care of this ? When does grouping take care and when do we divide by the number of similar items ?

Senior Manager
Joined: 21 Jun 2017
Posts: 399
Location: India
Concentration: Finance, Economics
Schools: IIM
GMAT 1: 620 Q47 V30
GPA: 3
WE: Corporate Finance (Commercial Banking)
Re: How many different arrangements are possible to place seven different  [#permalink]

### Show Tags

14 Nov 2019, 12:08
generis Bunuel

If the 3 math books were same, would we divide the answer by 3! ? Or the grouping i.e 4 + 1 would take care of this ? When does grouping take care and when do we divide by the number of similar items ?

IF the three maths books were same 5! will be enough, one dos not need to multiply by 3!

Kudos, if this helped.
Re: How many different arrangements are possible to place seven different   [#permalink] 14 Nov 2019, 12:08
Display posts from previous: Sort by