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

 It is currently 15 Feb 2019, 23:25

### 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 February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT Strategy Webinar

February 16, 2019

February 16, 2019

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# A restaurant is hanging 7 large tiles on its wall in a single row

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 02 Jan 2017
Posts: 307
A restaurant is hanging 7 large tiles on its wall in a single row  [#permalink]

### Show Tags

17 Feb 2017, 15:37
2
00:00

Difficulty:

15% (low)

Question Stats:

78% (01:07) correct 22% (01:41) wrong based on 68 sessions

### HideShow timer Statistics

A restaurant is hanging 7 large tiles on its wall in a single row. How many arrangements of tiles are possible if there are 3 white tiles and 4 blue tiles?

A. 35
B. 12
C. 21
D. 84
E. 28
Math Expert
Joined: 02 Aug 2009
Posts: 7334
Re: A restaurant is hanging 7 large tiles on its wall in a single row  [#permalink]

### Show Tags

17 Feb 2017, 18:40
vikasp99 wrote:
A restaurant is hanging 7 large tiles on its wall in a single row. How many arrangements of tiles are possible if there are 3 white tiles and 4 blue tiles?

A. 35
B. 12
C. 21
D. 84
E. 28

Hi..

Total ways these 7 tiles can be arranged =7!
However these contain duplicity as 3 tiles are of one colour and other 4 are of other colour..
So eliminating these = $$\frac{7!}{3!4!}$$=35

A
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html
4) Base while finding % increase and % decrease : https://gmatclub.com/forum/percentage-increase-decrease-what-should-be-the-denominator-287528.html

GMAT Expert

Senior Manager
Joined: 17 Mar 2014
Posts: 438
Re: A restaurant is hanging 7 large tiles on its wall in a single row  [#permalink]

### Show Tags

20 Jan 2019, 07:21
vikasp99 wrote:
A restaurant is hanging 7 large tiles on its wall in a single row. How many arrangements of tiles are possible if there are 3 white tiles and 4 blue tiles?

A. 35
B. 12
C. 21
D. 84
E. 28

Hello Bunuel,

Isn't this question confusing. 3 White tiles could be different white tiles and/or 4 blue tiles could be different blue tiles ? How we can make sure that all white/blue tiles are similar ?

Thanks,
Amm
Manager
Joined: 15 Feb 2018
Posts: 242
Re: A restaurant is hanging 7 large tiles on its wall in a single row  [#permalink]

### Show Tags

20 Jan 2019, 16:59
ammuseeru
I understand your attention to detail (based on some convoluted and tricky gmat questions), but it I have not found it necessary for combination questions. Most people (including and especially me) find this section confusing. The questions ask straight forward questions and simply require application of rules. This question tests 'permutation with repeated elements'.

$$P(n; n_1, n_2, . . . , n_k) = \frac{n!}{n_1! n_2! . . . n_k!}$$
Re: A restaurant is hanging 7 large tiles on its wall in a single row   [#permalink] 20 Jan 2019, 16:59
Display posts from previous: Sort by