A little lockdown maths question for you...
A little lockdown maths question for you...
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Discussion

Kermit power

Original Poster:

29,622 posts

242 months

Friday 1st May 2020
quotequote all
Morning folks,

With the number of people furloughed and bored, there's an increase in posts on Facebook along the lines of "I've been nominated by my friend to post one photo per day for the next ten days of the Brussels Sprouts which most made me hate Brussels Sprouts in my youth, and tag a friend to do likewise".

So here's the question... If everyone tagged in such a post religiously did post a single picture per day for ten days and tag a friend, and assuming that there's no duplication of people asking people who've already been tagged, how long would it take until every one of the 2.5Bn regular users on Facebook had been tagged?

I don't know the answer btw, but in light of all the discussion of r0 as relates to Covid, I'm sure someone must know how to work it out? My brain was hurting over the fact that whilst every person infects ten other people, they only infect one at a time, and only for ten days...

sc0tt

18,294 posts

230 months

Friday 1st May 2020
quotequote all
9 Days ... and a bit.

Edited by sc0tt on Friday 1st May 12:20

Kermit power

Original Poster:

29,622 posts

242 months

Friday 1st May 2020
quotequote all
Please also add the maths to explain any answers! smile

Shakermaker

11,317 posts

129 months

Friday 1st May 2020
quotequote all
That depends how long it takes for the first person who is tagged to go ahead and tag the next person, surely?

Kermit power

Original Poster:

29,622 posts

242 months

Friday 1st May 2020
quotequote all
Shakermaker said:
That depends how long it takes for the first person who is tagged to go ahead and tag the next person, surely?
Let's assume that everyone tags one person per day on days one to ten from when they get tagged.

Shakermaker

11,317 posts

129 months

Friday 1st May 2020
quotequote all
Kermit power said:
Let's assume that everyone tags one person per day on days one to ten from when they get tagged.
For the 2.5 billion people to be tagged, that needs 1.25bn to have tagged them the day before, which means 635m the day before etc..

Halving it every day gets you 32 (and a bit) days.

From Day 1 to Day 10, you'd have 512 people in the chain

Shakermaker

11,317 posts

129 months

Friday 1st May 2020
quotequote all
bit of trimming gone on here?

Kermit power

Original Poster:

29,622 posts

242 months

Friday 1st May 2020
quotequote all
Shakermaker said:
Kermit power said:
Let's assume that everyone tags one person per day on days one to ten from when they get tagged.
For the 2.5 billion people to be tagged, that needs 1.25bn to have tagged them the day before, which means 635m the day before etc..

Halving it every day gets you 32 (and a bit) days.

From Day 1 to Day 10, you'd have 512 people in the chain
Does that take into account, though, that people are only "infectious" (tagging) for ten days?

Shakermaker

11,317 posts

129 months

Friday 1st May 2020
quotequote all
Erm now I don’t know... I’ve asked Rachel Riley. I’ll let you know if she replies!

The Dictator

1,491 posts

169 months

Thursday 7th May 2020
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I fking hate all these 10 pics ten days nominations and will not get involved in any of them.

Partly it's the "no explanation" part, as I would actually want to know the why, otherwise it is yet another random photo polluting my feed, and it's not like there aren't enough of them already!!

fk off and nominate someone else you .

Shakermaker

11,317 posts

129 months

Thursday 7th May 2020
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It certainly isn't compulsory, and you're in luck because at the moment, the Facebook police who would normally monitor this are on full patrol having to deal with people not making a big enough deal about how many rainbows they have painted