GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 23 Feb 2019, 03:30

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
Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
  • Free GMAT RC Webinar

     February 23, 2019

     February 23, 2019

     07:00 AM PST

     09:00 AM PST

    Learn reading strategies that can help even non-voracious reader to master GMAT RC. Saturday, February 23rd at 7 AM PT
  • FREE Quant Workshop by e-GMAT!

     February 24, 2019

     February 24, 2019

     07:00 AM PST

     09:00 AM PST

    Get personalized insights on how to achieve your Target Quant Score.

If a marching band has 72 members that always march in fo

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

Hide Tags

 
Intern
Intern
avatar
Joined: 09 Feb 2012
Posts: 47
If a marching band has 72 members that always march in fo  [#permalink]

Show Tags

New post Updated on: 20 Aug 2012, 10:42
1
5
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

60% (00:18) correct 40% (01:03) wrong based on 19 sessions

HideShow timer Statistics

If a marching band has 72 members that always march in formations of at least three rows and at least 3 members in each row, how many different formations can they march in?

OA: 8


Many thanks guys!

Originally posted by NYC5648 on 20 Aug 2012, 10:27.
Last edited by Bunuel on 20 Aug 2012, 10:42, edited 1 time in total.
Edited the question.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 53066
Re: If a marching band has 72 members that always march in fo  [#permalink]

Show Tags

New post 20 Aug 2012, 10:34
1
NYC5648 wrote:
If a marching band has 72 members that always march in formations of at least three rows and at least 3 members in each row, how many different formations can they march in?

OA: 8

Many thanks guys!


ROWS - PEOPLE IN EACH ROW
3 ------------- 24 (3*24=72)
4 ------------- 18
6 ------------- 12
8 ------------- 9

9 ------------- 8
12 ----------- 6
18 ----------- 4
24 ----------- 3

Total of 8 different formations.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Manager
Manager
avatar
Joined: 05 Jul 2012
Posts: 64
Location: India
Concentration: Finance, Strategy
GMAT Date: 09-30-2012
GPA: 3.08
WE: Engineering (Energy and Utilities)
Re: If a marching band has 72 members that always march in fo  [#permalink]

Show Tags

New post 20 Aug 2012, 17:58
1
Bunuel wrote:
NYC5648 wrote:
If a marching band has 72 members that always march in formations of at least three rows and at least 3 members in each row, how many different formations can they march in?

OA: 8

Many thanks guys!


ROWS - PEOPLE IN EACH ROW
3 ------------- 24 (3*24=72)
4 ------------- 18
6 ------------- 12
8 ------------- 9

9 ------------- 8
12 ----------- 6
18 ----------- 4
24 ----------- 3

Total of 8 different formations.



How did you find out that the number of people in each row is the same ??
Senior Manager
Senior Manager
avatar
B
Joined: 13 Oct 2016
Posts: 367
GPA: 3.98
Re: If a marching band has 72 members that always march in fo  [#permalink]

Show Tags

New post 16 Dec 2016, 04:55
1
NYC5648 wrote:
If a marching band has 72 members that always march in formations of at least three rows and at least 3 members in each row, how many different formations can they march in?

OA: 8


Many thanks guys!


We have \(X\) rows and \(Y\) columns (members in each row)

\(X*Y = 72\)

We need to find out the number of ways 72 can be expressed as a product of 2 factors.
\(72 = 2^3*3^2\)

# of ways = \(\frac{(3+1)*(2+1)}{2} = 6\)

But we can’t use this answer because in our question ORDER MATTERS. Rows are different from the columns (number of people in a row). \(3*24\) here is different from \(24*3\). Hence we should not divide by 2 and we get 12 total possibilities.

Next step: we need to take into consideration additional restriction: \(X ≥ 3\), \(Y ≥ 3\).

We need to deduct following 4 cases from our total set: \(1*72\), \(2*36\) and \(72*1\), \(36*2\)

Final answer: \(12 – 4 = 8\)
Intern
Intern
User avatar
B
Joined: 12 Feb 2018
Posts: 12
Re: If a marching band has 72 members that always march in fo  [#permalink]

Show Tags

New post 20 Feb 2019, 15:09
Bunuel wrote:
NYC5648 wrote:
If a marching band has 72 members that always march in formations of at least three rows and at least 3 members in each row, how many different formations can they march in?

OA: 8

Many thanks guys!


ROWS - PEOPLE IN EACH ROW
3 ------------- 24 (3*24=72)
4 ------------- 18
6 ------------- 12
8 ------------- 9

9 ------------- 8
12 ----------- 6
18 ----------- 4
24 ----------- 3

Total of 8 different formations.


Bunuel
The issue with this solution is that it´s assumed that all rows will request the same number of participants. However whether we consider minimum of 3 row within 3 people in each, we will have a significant increase in this number...
GMAT Club Bot
Re: If a marching band has 72 members that always march in fo   [#permalink] 20 Feb 2019, 15:09
Display posts from previous: Sort by

If a marching band has 72 members that always march in fo

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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®.