Problem 783

A place to air possible concerns or difficulties in understanding ProjectEuler problems. This forum is not meant to publish solutions. This forum is NOT meant to discuss solution methods or giving hints how a problem can be solved.
Forum rules
As your posts will be visible to the general public you are requested to be thoughtful in not posting anything that might explicitly give away how to solve a particular problem.

This forum is NOT meant to discuss solution methods for a problem.

In particular don't post any code fragments or results.

Don't start begging others to give partial answers to problems

Don't ask for hints how to solve a problem

Don't start a new topic for a problem if there already exists one


See also the topics:
Don't post any spoilers
Comments, questions and clarifications about PE problems.
Post Reply
spidersanghvi
Posts: 1
Joined: Sun Dec 02, 2012 4:38 pm

Problem 783

Post by spidersanghvi »

So I do not know if asking this is fine but when I am calculating the value of E(2,2) I am getting the value 8.666667.Am I missing something?
User avatar
neverforget
Posts: 88
Joined: Sat Sep 16, 2006 10:10 pm

Re: Problem 783

Post by neverforget »

Please include the link to the problem in the first post, like this: Problem 783 (View Problem)

And to answer your question, you must be missing something because $E(2,2)$ is easy enough to verify by hand, and the stated value in the problem is definitely correct. I would suggest carefully rereading the problem statement, as that is usually where the problem lies when small examples don't match.
Image
PeterBurbery
Posts: 6
Joined: Thu Feb 24, 2022 6:12 pm

Re: Problem 783

Post by PeterBurbery »

I am wondering if the a sequence of balls is removed all at once or a ball is removed one by one.
User avatar
RobertStanforth
Administrator
Posts: 2666
Joined: Mon Dec 30, 2013 11:25 pm

Re: Problem 783

Post by RobertStanforth »

PeterBurbery wrote: Thu Feb 24, 2022 6:13 pm I am wondering if the a sequence of balls is removed all at once or a ball is removed one by one.
"On each turn [...] $2k$ random balls are removed from the urn"
These $2k$ are selected in such a way that any possible choice of $2k$ is as likely as any other.
It doesn't make any difference to the distribution of $B_t$ whether all $2k$ balls for turn $t$ are selected/removed at once, or one at a time.
PeterBurbery
Posts: 6
Joined: Thu Feb 24, 2022 6:12 pm

Re: Problem 783

Post by PeterBurbery »

I am wondering if this is a place where I can ask questions about Wolfram mathematica and functions.
PeterBurbery
Posts: 6
Joined: Thu Feb 24, 2022 6:12 pm

Re: Problem 783

Post by PeterBurbery »

I'm just wondering but what does the expectation of mean?
Further define E(n,k) as the expectation of
User avatar
jaap
Posts: 588
Joined: Tue Mar 25, 2008 3:57 pm
Contact:

Re: Problem 783

Post by jaap »

PeterBurbery wrote: Thu Feb 24, 2022 8:08 pm I'm just wondering but what does the expectation of mean?
Further define E(n,k) as the expectation of
It means the expected value.
Post Reply