PS - Movies (m05q27) : Retired Discussions [Locked]
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 20 Jan 2017, 20:54

### 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

# PS - Movies (m05q27)

Author Message
Senior Manager
Joined: 12 Mar 2007
Posts: 274
Followers: 1

Kudos [?]: 83 [0], given: 2

### Show Tags

21 Aug 2007, 20:25
2
This post was
BOOKMARKED
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Carly has 3 movies that she can watch during the weekend: 1 Action movie, 1 Comedy, and 1 Drama. However, she needs to watch the Drama 3 times. Assuming Carly has time for 5 movies and intends to watch all of them, in how many ways can she do so?

(A) 6
(B) 20
(C) 24
(D) 60
(E) 120

Source: GMAT Club Tests - hardest GMAT questions

REVISED VERSION OF THIS QUESTION IS HERE: ps-movies-m05q27-50926.html#p1109959
Director
Joined: 03 May 2007
Posts: 886
Schools: University of Chicago, Wharton School
Followers: 6

Kudos [?]: 190 [0], given: 7

### Show Tags

22 Aug 2007, 08:04
leeye84 wrote:
Fistail wrote:
leeye84 wrote:
Carly has 3 movies that she can watch during the weekend: 1 Action movie, 1 Comedy, and 1 Drama. However, she needs to watch the Drama 3 times. Assuming Carly has time for 5 movies and intends to watch all of them, in how many ways can she do so?

1) 6
2) 20
3) 24
4) 60
5) 120

= 5!/3!
=20

Could you be a bit more specific? I'm not sure how to get to the answer.

it is 5! but when there is a repetition you need to divide total by the repetitive number's factorial.
so it is 5!/3!.
Manager
Joined: 15 Aug 2007
Posts: 70
Followers: 2

Kudos [?]: 5 [2] , given: 0

### Show Tags

22 Aug 2007, 08:11
2
KUDOS
leeye84 wrote:
Fistail wrote:
leeye84 wrote:
Carly has 3 movies that she can watch during the weekend: 1 Action movie, 1 Comedy, and 1 Drama. However, she needs to watch the Drama 3 times. Assuming Carly has time for 5 movies and intends to watch all of them, in how many ways can she do so?

1) 6
2) 20
3) 24
4) 60
5) 120

= 5!/3!
=20

Could you be a bit more specific? I'm not sure how to get to the answer.

Its clear form question that he has to watch 3 drama movie,1 Action movie and 1 Comedy in 5 movie times..
We juss have to find out the ways of arranging it.

When these type of questions come in which u have to arrange n things on n places where m are similar things.. Ways =n!/m!
So 5!/3! is the answer, 5 movies, 3 are same

Manager
Status: Waiting to hear from University of Texas at Austin
Joined: 24 May 2010
Posts: 76
Location: Changchun, China
Schools: University of Texas at Austin, Michigan State
Followers: 5

Kudos [?]: 56 [1] , given: 4

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

28 Jul 2010, 05:20
1
KUDOS
I think rewording this question is appropriate because it is part of the quantitative section not the verbal. The verb "intends" should be changed to "must"

Other than that I came up with the possible solutions thinking about it this way.

The are 5 movie slots available

The choices (in the bag) are $$Drama^1$$, $$Drama^2$$, $$Drama^3$$, Action, and Comedy.

For the first slot you have 5 choices
second slot there are 4 choices and so on.

So we know we have 5 x 4 x 3 x 2 x 1 (5!) ways to arrange the movies.
5! = 120

Then we have to find a way to account for duplication. As far as the movie watcher is concerned watching$$Drama^1$$ is the same as $$Drama^2$$

I knew E was incorrect because of duplication and A seemed too few combinations considering there are 5 time slots. So figuring I was nearing the perpetual 2 minute time limit, I guessed at B. My thought was 120 / x = 20 x=6 sounds about right.

Others have suggested you can divide by the duplication (3!) to get a sure answer.

At this point I made the guess for B and I am crossing my fingers
Manager
Joined: 20 Jul 2010
Posts: 198
Followers: 2

Kudos [?]: 114 [0], given: 7

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

28 Jul 2010, 06:12
IMO B.

She wants to watch drama 3 times.. so she has 5C3 slots for drama movies = 10 slots.
The other 2 slots can be chosen in 2 * 1 ways = 2 ways..

Therefore total ways = 10 * 2 = 20...
_________________

Gotta hit the 700 score this time... 3rd time lucky !
Give me some kudos... Like you, even I need them badly

Intern
Joined: 26 Jul 2010
Posts: 9
Location: Asia
WE 1: Manufacturing & Planning
WE 2: Supply Chain Management
Followers: 0

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

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

28 Jul 2010, 10:04
Explanation:
She has to watch 1 Action
movie(a), 1 Comedy(c), and 1 Drama(d). However the drama movie needs to be watched thrice which is like watching the same movie 3 times.
We can start working out like this...
acddd

The total number of movies to be watched is 5, of which 3 are repeated. Therefore the answer works out to 5!/3! Which is equal to 20

Posted from my mobile device
Intern
Joined: 26 Jul 2010
Posts: 9
Location: Asia
WE 1: Manufacturing & Planning
WE 2: Supply Chain Management
Followers: 0

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

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

28 Jul 2010, 10:05
Explanation:
She is required to watch 1 Action
movie(a), 1 Comedy movie(c), and 1 Drama movie(d). However the drama movie needs to be watched thrice which is like watching the same movie 3 times.
We can start working out like this...
acddd

The total number of movies to be watched is 5, of which 3 are repeated. Therefore the answer works out to 5!/3! Which is equal to 20

Posted from my mobile device
Manager
Joined: 13 Jul 2010
Posts: 169
Followers: 1

Kudos [?]: 73 [0], given: 7

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

28 Jul 2010, 17:36
I quickly guessed at the question and instead of using the formula thought intuitively:

DDDCA - How many different ways can I arrange these 5 letters? 5! however the 3 D's are all the same so 3! needs to be deducted due to double counting. so the answer is 5!/3! or 20.
Intern
Joined: 15 Jun 2010
Posts: 2
Followers: 0

Kudos [?]: 0 [0], given: 2

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

02 Aug 2010, 07:00
One more way of solving:
(5C3x2C1)=20
Senior Manager
Joined: 08 Nov 2010
Posts: 417
Followers: 7

Kudos [?]: 105 [0], given: 161

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

01 Aug 2011, 05:04
bddurgap wrote:
One more way of solving:
(5C3x2C1)=20

5C3 is choosing 3 spots out of 5 for the drama movies.

Im missing the explanation for 2C1. thanks.
_________________
Intern
Joined: 30 Aug 2010
Posts: 23
Followers: 0

Kudos [?]: 0 [0], given: 2

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

01 Aug 2011, 05:41
For problems like these, I tend to go straight to the anagram method

ACDDD

5 total letters = 5!

Divide that by the product of the factorials of all the different letters = 1! (A) x 1! (C) x 3! (there are 3 D's)

5! / 3! = 20
Senior Manager
Joined: 05 Jul 2010
Posts: 359
Followers: 15

Kudos [?]: 51 [0], given: 17

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

01 Aug 2011, 06:54
leeye84 wrote:
Carly has 3 movies that she can watch during the weekend: 1 Action movie, 1 Comedy, and 1 Drama. However, she needs to watch the Drama 3 times. Assuming Carly has time for 5 movies and intends to watch all of them, in how many ways can she do so?

(A) 6
(B) 20
(C) 24
(D) 60
(E) 120

[Reveal] Spoiler: OA
B

Source: GMAT Club Tests - hardest GMAT questions

There are multiple ways to solve this problem:

Q: There are 5 movie slots to fill, such that, D movie watched 3 time, and A and C movies once each.

Sol 1: also known as Anagram
M1 M2 M3 M4 M5
Total ways = 5! , if all different movies
But D repeats 3 times and others once, so
Total conditional ways = 5!/(3!*1!*1!) = 20

Sol 2:
Total conditional ways =
(number of ways to select movie slots where D will be played)*(number of ways to select movie slots where A will be played from the remaining places)*(number of ways to select movie slots where C will be played from the remaining places)
= 5C3 * 2C1 * 1C1
= 10 * 2 * 1
= 20

There are few other ways but these are something easy to comprehend.

Hope these helps!
Director
Joined: 21 Dec 2009
Posts: 591
Concentration: Entrepreneurship, Finance
Followers: 18

Kudos [?]: 662 [0], given: 20

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

01 Aug 2011, 09:56
took some time in drawing a correlation between this question and the total number
of ways of arrangements of items: ABDDD
ABDDD: 5!/3! = 20: total 5 items but 3 identical.

A and B represent different movies, and D represents drama.
In satisfying the condition (ABDDD) for 5 different time slots
we therefore require: 5! / 3!(repetitions)
_________________

KUDOS me if you feel my contribution has helped you.

Intern
Joined: 29 Jul 2011
Posts: 2
Followers: 0

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

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

02 Aug 2011, 09:35
This problem can be thought of as a permutation problem.
Since we have 5 slots to fill with movies A,B,D,D,D, we can calculate number of ways A and B can be put into 5 positions.
Rest of the positions will be filled by D hence it does not matter how we distribute remaining 3 Ds in 3 positions.
Which is 5P2 = 5!/(5-2)! = 5!/3! = 20
Manager
Joined: 14 Mar 2011
Posts: 87
Followers: 1

Kudos [?]: 41 [0], given: 21

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

10 Aug 2011, 11:07
5C3 X 2C1 = 5!/(3!X2!) *2! = 5!/3! = 20
Math Expert
Joined: 02 Sep 2009
Posts: 36583
Followers: 7087

Kudos [?]: 93289 [2] , given: 10555

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

03 Aug 2012, 04:10
2
KUDOS
Expert's post
leeye84 wrote:
Carly has 3 movies that she can watch during the weekend: 1 Action movie, 1 Comedy, and 1 Drama. However, she needs to watch the Drama 3 times. Assuming Carly has time for 5 movies and intends to watch all of them, in how many ways can she do so?

(A) 6
(B) 20
(C) 24
(D) 60
(E) 120

[Reveal] Spoiler: OA
B

Source: GMAT Club Tests - hardest GMAT questions

Below is a revised version of this question:

Carly has three movies that she can watch during the weekend: an action movie, a comedy, or a drama. However, she wants to watch the same drama movie three times, an action movie once and a comedy movie also once. In how many different ways can she arrange these five screenings?

A. 6
B. 20
C. 24
D. 60
E. 120

The number of different ways Carly can watch Drama, Drama, Drama, Action, Comedy (DDDAC) is basically the number of arrangements of 5 letters DDDAC out of which 3 D's are identical, so it's $$\frac{5!}{3!}=20$$.

_________________
Intern
Status: Looking for High GMAT Score
Joined: 19 May 2012
Posts: 37
Location: India
Concentration: Strategy, Marketing
WE: Marketing (Internet and New Media)
Followers: 0

Kudos [?]: 6 [0], given: 58

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

03 Aug 2012, 04:29
ACDDD

5!/3! = 20

B

what percentile question is it?

Did not require more than 1 min
_________________

“The best time to plant a tree was 20 years ago. The second best time is now.” – Chinese Proverb

Manager
Status: I will not stop until i realise my goal which is my dream too
Joined: 25 Feb 2010
Posts: 235
Schools: Johnson '15
Followers: 2

Kudos [?]: 50 [0], given: 16

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

03 Aug 2012, 21:31
leeye84 wrote:
Carly has 3 movies that she can watch during the weekend: 1 Action movie, 1 Comedy, and 1 Drama. However, she needs to watch the Drama 3 times. Assuming Carly has time for 5 movies and intends to watch all of them, in how many ways can she do so?

(A) 6
(B) 20
(C) 24
(D) 60
(E) 120

[Reveal] Spoiler: OA
B

Source: GMAT Club Tests - hardest GMAT questions

Carly has options to watch 5 movies, but she as 1 Action, 1 Comedy and 1 Drama Movie...

for 5 options she has 3 Drama movies, she will watch the same...so DDD and Action A and Comedy C

so 5 movies she has is DDDAC

hence these can be arranged in 5! ways

now in the above arrangement there can be arrangements of just DDD in 3! ..so the new arrangement for her requirement is 5!/3! = 5*4 = 20 which is B
Manager
Joined: 14 Jun 2012
Posts: 66
Followers: 0

Kudos [?]: 13 [0], given: 1

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

05 Aug 2012, 16:09
I started with the combinations but got caught up in whether the sequence mattered or not. So then switched to listing out the movies as DDDAC. Worked on this approach for a while and was not getting anywhere. In the end I chose A which was wrong.

The above explanations have surely helped me understand where I was going wrong. The anagram explanation was particularly helpful and I will surely apply it the next time I face such a problem.
_________________

My attempt to capture my B-School Journey in a Blog : tranquilnomadgmat.blogspot.com

There are no shortcuts to any place worth going.

Director
Joined: 22 Mar 2011
Posts: 612
WE: Science (Education)
Followers: 100

Kudos [?]: 891 [0], given: 43

Re: PS - Movies (m05q27) [#permalink]

### Show Tags

05 Aug 2012, 23:35
avrgmat wrote:
I started with the combinations but got caught up in whether the sequence mattered or not. So then switched to listing out the movies as DDDAC. Worked on this approach for a while and was not getting anywhere. In the end I chose A which was wrong.

The above explanations have surely helped me understand where I was going wrong. The anagram explanation was particularly helpful and I will surely apply it the next time I face such a problem.

Try to use simple logic: Carly has to watch 5 movies. She wants to see the drama 3 times, and the other two movies, once each.
She can watch them in different orders, and here definitely order matters.

To watch the action movie, she can chose from 5 possibilities - either first, second, third, fourth or fifth movie.
Then, for the comedy, she can chose from 4 possibilities - any place left in the sequence, after the action movie was "placed".
All the remaining 3 slots, will be given to the drama movie.

Therefore, a total of 5*4=20 possibilities for the orders in which she can watch the movies.

_________________

PhD in Applied Mathematics
Love GMAT Quant questions and running.

Re: PS - Movies (m05q27)   [#permalink] 05 Aug 2012, 23:35

Go to page    1   2    Next  [ 27 posts ]

Similar topics Replies Last post
Similar
Topics:
2 PS 4 05 Jun 2012, 21:51
3 ps 2 27 Mar 2011, 19:26
PS: m 15 #6 1 20 Jun 2009, 11:21
PS: m 15 #31 3 20 Jun 2009, 11:05
PS: Divisors 6 25 Feb 2009, 15:19
Display posts from previous: Sort by

# PS - Movies (m05q27)

Moderator: Bunuel

 Powered by phpBB © phpBB Group and phpBB SEO 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®.