Author 
Message 
TAGS:

Hide Tags

Senior Manager
Joined: 13 Aug 2012
Posts: 464
Concentration: Marketing, Finance
GPA: 3.23

Re: Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
27 Dec 2012, 23:05
1
This post was BOOKMARKED
reply2spg wrote: Six mobsters have arrived at the theater for the premiere of the film “Goodbuddies.” One of the mobsters, Frankie, is an informer, and he's afraid that another member of his crew, Joey, is on to him. Frankie, wanting to keep Joey in his sights, insists upon standing behind Joey in line at the concession stand, though not necessarily right behind him. How many ways can the six arrange themselves in line such that Frankie’s requirement is satisfied?
A. 6 B. 24 C. 120 D. 360 E. 720 Solution 1: How many ways to arrange 6 without restriction? 6! In the total of ways, half of the time J will be behind F or F behind J. \(=6!/2 = 360\) Solution 2: To get a little more practice on permutations...We could count the possibilities of J(...)F. 0 person in between: 5 1 person in between: 4 2 persons in between: 3 3 persons in between: 2 4 persons in between: 1 (5 + 4 + 3 + 2 + 1) * 4! = 360
_________________
Impossible is nothing to God.



Manager
Status: struggling with GMAT
Joined: 06 Dec 2012
Posts: 213
Location: Bangladesh
Concentration: Accounting
GMAT Date: 04062013
GPA: 3.65

Re: Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
28 Feb 2013, 10:57
thanks to all for explanation.Finally i understand the concept................



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15939

Re: Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
01 Apr 2014, 07:47
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15939

Re: Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
23 May 2015, 16:52
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Manager
Joined: 14 Mar 2014
Posts: 151

Six mobsters have arrived at the theater [#permalink]
Show Tags
10 Aug 2015, 08:24
Six mobsters have arrived at the theater for the premiere of a film. One of the mobsters, Eden, is an informer, and he is afraid that another member of his crew, Costa, is on to him. Eden wanting to keep Costa in his sights, insists upon standing behind Costa in line at the concession stand. how many ways can the six arrange themselves in line such that Eden's requirement is satisfied? a. 6 b. 24 c. 120 d. 360 e. 720
_________________
I'm happy, if I make math for you slightly clearer And yes, I like kudos ¯\_(ツ)_/¯



Manager
Joined: 14 Mar 2014
Posts: 151

Re: Six mobsters have arrived at the theater [#permalink]
Show Tags
10 Aug 2015, 08:39
VenoMfTw wrote: Six mobsters have arrived at the theater for the premiere of a film. One of the mobsters, Eden, is an informer, and he is afraid that another member of his crew, Costa, is on to him. Eden wanting to keep Costa in his sights, insists upon standing behind Costa in line at the concession stand. how many ways can the six arrange themselves in line such that Eden's requirement is satisfied?
a. 6 b. 24 c. 120 d. 360 e. 720 Half of the total possible ways Costa will be ahead of Eden And for other half Eden will be ahead of Costa Total possible ways = 6! = 720 ways Thus for required = 720/2 =360
_________________
I'm happy, if I make math for you slightly clearer And yes, I like kudos ¯\_(ツ)_/¯



Intern
Joined: 27 Apr 2015
Posts: 32
Location: India
WE: Operations (Telecommunications)

Re: Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
31 Aug 2015, 21:38
Now the method I'm discussing has already been shared, but the explanations were not too clear for me, so sharing a detailed explanation. Now following can be the available arrangements (please note that the question requires us to place Frankie behind Joey in line, though not necessarily right behind him): _ _ _ _ _ F: when F is at the last, there are 5 options for J and the rest can be arranged in 4! ways: 5x4! _ _ _ _ F _: when F is at the second last position, there are 4 options for J and the rest can be arranged in 4! ways: 4x4! _ _ _ F _ _: when F is at the third last position, there are 3 options for J and the rest can be arranged in 4! ways: 3x4! _ _ F _ _ _: when F is at the third third spot from the front, there are 2 options for J and the rest can be arranged in 4! ways: 2x4! _ F _ _ _: when F is at the third third spot from the front, there is only 1 options for J and the rest can be arranged in 4! ways: 4! Now F can not be placed at the first spot as he has to be behind J, so above are al the situations possible and the sum would give us the total arrangements. total arrangements = 5x4! + 4x4! + 3x4! + 2x4! + 4! = (5+4+3+2+1)4! = 15x4! = 360



Intern
Joined: 11 Dec 2012
Posts: 40

Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
01 Sep 2015, 03:27
Six mobsters have arrived at the theater for the premiere of the film “Goodbuddies.” One of the mobsters, Frankie, is an informer, and he's afraid that another member of his crew, Joey, is on to him. Frankie, wanting to keep Joey in his sights, insists upon standing behind Joey in line at the concession stand, though not necessarily right behind him. How many ways can the six arrange themselves in line such that Frankie’s requirement is satisfied? A. 6 B. 24 C. 120 D. 360 E. 720
Attachments
Six Mobsters.JPG [ 59.89 KiB  Viewed 574 times ]



Manager
Joined: 18 Sep 2015
Posts: 109
GMAT 1: 610 Q43 V31 GMAT 2: 610 Q47 V27 GMAT 3: 650 Q48 V31 GMAT 4: 700 Q49 V35
WE: Project Management (Health Care)

Re: Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
24 May 2016, 14:51
reply2spg wrote: Six mobsters have arrived at the theater for the premiere of the film “Goodbuddies.” One of the mobsters, Frankie, is an informer, and he's afraid that another member of his crew, Joey, is on to him. Frankie, wanting to keep Joey in his sights, insists upon standing behind Joey in line at the concession stand, though not necessarily right behind him. How many ways can the six arrange themselves in line such that Frankie’s requirement is satisfied?
A. 6 B. 24 C. 120 D. 360 E. 720 We can pick 2 place for Frankie and Joey (2 of 6) and multiply by the other 4! possiblity for the rest. (6!/2!*4!)*4!=360.



Intern
Joined: 12 Dec 2016
Posts: 13

Manhattan freePrep combination question  can't understand ! [#permalink]
Show Tags
12 Dec 2016, 13:53
Heyhey! This is my first ever post here. I have my gmat at 19th of December and need to pass 600 limit, however i had in total 18 days to study and i really do not believe in myself do pass 600 limit, since i had almost 0 math knowledge left ... thanks to my university. Anyway; this is the question From manhattan freePrep test) "Six mobsters have arrived at the theater for the premiere of the film “Goodbuddies.” One of the mobsters, Frankie, is an informer, and he's afraid that another member of his crew, Joey, is on to him. Frankie, wanting to keep Joey in his sights, insists upon standing behind Joey in line at the concession stand, though not necessarily right behind him. How many ways can the six arrange themselves in line such that Frankie’s requirement is satisfied?" Solution: "Ignoring Frankie's requirement for a moment, observe that the six mobsters can be arranged 6! or 6 x 5 x 4 x 3 x 2 x 1 = 720 different ways in the concession stand line. In each of those 720 arrangements, Frankie must be either ahead of or behind Joey. Logically, since the combinations favor neither Frankie nor Joey, each would be behind the other in precisely half of the arrangements. Therefore, in order to satisfy Frankie's requirement, the six mobsters could be arranged in 720/2 = 360 different ways." Where i don't understand:It says that Frankie has to stay behind Joey, however in the answer it explicitly says that Frankie must be either ahead of or behind Joey. This part really contradicts each other, and there is no way i can extract any logic from the question yet begin the process of solving. I'd love to hear some advices from experts Kind regards, Mesut Törün



Math Expert
Joined: 02 Sep 2009
Posts: 39626

Re: Six mobsters have arrived at the theater for the premiere of [#permalink]
Show Tags
12 Dec 2016, 13:58
mesutthefail wrote: Heyhey! This is my first ever post here. I have my gmat at 19th of December and need to pass 600 limit, however i had in total 18 days to study and i really do not believe in myself do pass 600 limit, since i had almost 0 math knowledge left ... thanks to my university. Anyway; this is the question From manhattan freePrep test) "Six mobsters have arrived at the theater for the premiere of the film “Goodbuddies.” One of the mobsters, Frankie, is an informer, and he's afraid that another member of his crew, Joey, is on to him. Frankie, wanting to keep Joey in his sights, insists upon standing behind Joey in line at the concession stand, though not necessarily right behind him. How many ways can the six arrange themselves in line such that Frankie’s requirement is satisfied?" Solution: "Ignoring Frankie's requirement for a moment, observe that the six mobsters can be arranged 6! or 6 x 5 x 4 x 3 x 2 x 1 = 720 different ways in the concession stand line. In each of those 720 arrangements, Frankie must be either ahead of or behind Joey. Logically, since the combinations favor neither Frankie nor Joey, each would be behind the other in precisely half of the arrangements. Therefore, in order to satisfy Frankie's requirement, the six mobsters could be arranged in 720/2 = 360 different ways." Where i don't understand:It says that Frankie has to stay behind Joey, however in the answer it explicitly says that Frankie must be either ahead of or behind Joey. This part really contradicts each other, and there is no way i can extract any logic from the question yet begin the process of solving. I'd love to hear some advices from experts Kind regards, Mesut Törün Merging topics. Please refer to the previous discussion. Also, please read carefully and follow: rulesforpostingpleasereadthisbeforeposting133935.html Thank you.
_________________
New to the Math Forum? Please read this: 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? Extrahard Quant Tests with Brilliant Analytics




Re: Six mobsters have arrived at the theater for the premiere of
[#permalink]
12 Dec 2016, 13:58



Go to page
Previous
1 2
[ 31 posts ]




