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.
It appears that you are browsing the GMAT Club forum unregistered!
Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club
Registration gives you:
Tests
Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.
Applicant Stats
View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more
Books/Downloads
Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
Each person out of 6 has 6 options, hence total # of outcomes is 6^6;
Favorable outcomes will be 6!, which is # of ways to assign 6 different buttons to 6 people: 1-2-3-4-5-6 (floors) A-B-C-D-E-F (persons) B-A-C-D-E-F (persons) B-C-A-D-E-F (persons) ... So basically # of arrangements of 6 distinct objects: 6!.
Re: Six Six people are on an elevator that stops at exactly 6 [#permalink]
19 Feb 2012, 05:55
Hi, could you please tell me the mistake in the following logic?
First person entering pushes one button, it doesn't matter which: p=1 Second person pushes a button that has not been pressed before. Since one is already pushed, only 5 remain: p=5/6 Same logic for third person: p=4/6 . . .
This leaves us with The probability of all pushing a different button of: 1*5/6*4/6*4/6*2/6*1/6 or 5!/6^5
Re: Six Six people are on an elevator that stops at exactly 6 [#permalink]
19 Feb 2012, 10:48
Expert's post
Gwydion wrote:
Hi, could you please tell me the mistake in the following logic?
First person entering pushes one button, it doesn't matter which: p=1 Second person pushes a button that has not been pressed before. Since one is already pushed, only 5 remain: p=5/6 Same logic for third person: p=4/6 . . .
This leaves us with The probability of all pushing a different button of: 1*5/6*4/6*4/6*2/6*1/6 or 5!/6^5
Where's the mistake?
There is no mistake: 6!/6^6=(5!*6)/(6^5*6)=5!/6^5, the same answers. _________________
Re: Six Six people are on an elevator that stops at exactly 6 [#permalink]
07 Jun 2013, 06:52
4
This post received KUDOS
1
This post was BOOKMARKED
Gwydion wrote:
Hi, could you please tell me the mistake in the following logic?
First person entering pushes one button, it doesn't matter which: p=1 Second person pushes a button that has not been pressed before. Since one is already pushed, only 5 remain: p=5/6 Same logic for third person: p=4/6 . . .
This leaves us with The probability of all pushing a different button of: 1*5/6*4/6*4/6*2/6*1/6 or 5!/6^5
Where's the mistake?
Expanding on Gwydion's post - it is true that p=1, but because the answers all have 6 in them, the first person should be written as p=6/6 to make it easier to see the answer:
First person walks in and can push any button (6/6) Probability that second person will press any of the remaining 5 buttons (5/6) Probability that third person will press any of the remaining 4 buttons (4/6) Probability that fourth person will press any of the remaining 3 buttons (3/6) Probability that fifth person will press either of the remaining 2 buttons (2/6) Probability that sixth person will press the remaining button (1/6)
Re: Six people are on an elevator that stops at exactly 6 floors [#permalink]
10 Jul 2014, 01:31
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. _________________
Re: Six people are on an elevator that stops at exactly 6 floors [#permalink]
21 May 2015, 05:15
Does this logic work ?
Assuming we are calculating the options for that one person we use the number of floors are the options. Person A presses at the ground floor has 6 options, then 5 options as so on as he goes up. so 6*5*4*3*2*1 = 6!
Re: Six people are on an elevator that stops at exactly 6 floors [#permalink]
21 May 2015, 05:51
1
This post received KUDOS
Expert's post
shallow9323 wrote:
Does this logic work ?
Assuming we are calculating the options for that one person we use the number of floors are the options. Person A presses at the ground floor has 6 options, then 5 options as so on as he goes up. so 6*5*4*3*2*1 = 6!
Re: Six people are on an elevator that stops at exactly 6 floors [#permalink]
21 May 2015, 06:10
1
This post received KUDOS
EgmatQuantExpert wrote:
shallow9323 wrote:
Does this logic work ?
Assuming we are calculating the options for that one person we use the number of floors are the options. Person A presses at the ground floor has 6 options, then 5 options as so on as he goes up. so 6*5*4*3*2*1 = 6!
Re: Six people are on an elevator that stops at exactly 6 floors [#permalink]
21 May 2015, 06:20
Expert's post
shallow9323 wrote:
EgmatQuantExpert wrote:
shallow9323 wrote:
Does this logic work ?
Assuming we are calculating the options for that one person we use the number of floors are the options. Person A presses at the ground floor has 6 options, then 5 options as so on as he goes up. so 6*5*4*3*2*1 = 6!
The “3 golden nuggets” of MBA admission process With ten years of experience helping prospective students with MBA admissions and career progression, I will be writing this blog through...
You know what’s worse than getting a ding at one of your dreams schools . Yes its getting that horrid wait-listed email . This limbo is frustrating as hell . Somewhere...