|
|
A Brain Teaser
|
|
|
|
Posting Junkie
Join Date: Apr 2007
Location: Iowa, how long can this be? Does it really ruin the left column spacing?
Status:
Offline
|
|
You have 500 jellybeans in a single container. Five different colors, 100 of each color.
You're blindfolded.
What is the minimum number of jellybeans you need to pull out so that you are guaranteed to have 5 of a single color?
|
|
|
|
|
|
|
|
|
Games Meister
Join Date: Aug 2009
Location: Eternity
Status:
Offline
|
|
496?
Edit: Bwahaha, I read that as 100 of a single color. Where the hell did I get that from.
|
|
|
|
|
|
|
|
|
Professional Poster
Join Date: Aug 2007
Location: Just west of DC.
Status:
Offline
|
|
|
|
|
|
|
|
|
|
|
Professional Poster
Join Date: Dec 2006
Location: Maryland
Status:
Offline
|
|
Guaranteed?
I believe 496 is the answer.
Edit: Made the same mistake as dark....Hahaha. Okay. Naptime!
Edit 2: Dakar.....about that nap....
(
Last edited by Snow-i; Nov 2, 2010 at 12:12 PM.
)
|
|
|
|
|
|
|
|
|
Posting Junkie
Join Date: Apr 2007
Location: Iowa, how long can this be? Does it really ruin the left column spacing?
Status:
Offline
|
|
It's from a brain teaser book. I disagree with the answer given, but there's no explanation.
|
|
|
|
|
|
|
|
|
Games Meister
Join Date: Aug 2009
Location: Eternity
Status:
Offline
|
|
Originally Posted by Snow-i
Edit: Made the same mistake as dark....Hahaha.
I spy another mistake.
|
|
|
|
|
|
|
|
|
Professional Poster
Join Date: Dec 2006
Location: Maryland
Status:
Offline
|
|
Well, if you had 4 of every color you'd have 20, so 21 to make one of the colors 5?
|
|
|
|
|
|
|
|
|
Posting Junkie
Join Date: Apr 2007
Location: Iowa, how long can this be? Does it really ruin the left column spacing?
Status:
Offline
|
|
Yes, 21 is correct. It appears as if I tried to say that 4*4 = 20, and that's why I wasn't getting it.
|
|
|
|
|
|
|
|
|
Professional Poster
Join Date: Dec 2006
Location: Maryland
Status:
Offline
|
|
So how many would you need to pull out to make sure that you are guaranteed 5 of a single color left in the jar?
None. They are all already in the jar
|
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status:
Online
|
|
21, but that's too easy.
Edit: beat while mulling it over.
|
|
|
|
|
|
|
|
|
Moderator
Join Date: Jun 2000
Location: inside 128, north of 90
Status:
Offline
|
|
I would have guessed 5, since it's possible.
|
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Jun 2001
Location: planning a comeback !
Status:
Offline
|
|
Originally Posted by andi*pandi
I would have guessed 5, since it's possible.
Possible != guaranteed.
-t
|
|
|
|
|
|
|
|
|
Professional Poster
Join Date: Aug 2007
Location: Just west of DC.
Status:
Offline
|
|
5 colors. you could have 4 of each * 5 = 20 and one more would be 21.
revised answer - 21
|
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Dec 1999
Status:
Offline
|
|
Wait, does guarantee mean 100% probability? Although highly unlikely, you could pull 400 jelly beans of only the first 4 colors. You would need at least 401 jelly beans to guarantee at least 1 of each color.
|
"…I contend that we are both atheists. I just believe in one fewer god than
you do. When you understand why you dismiss all the other possible gods,
you will understand why I dismiss yours." - Stephen F. Roberts
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Jun 2001
Location: planning a comeback !
Status:
Offline
|
|
Originally Posted by olePigeon
401, I think. Although highly improbable, you could pull 400 jellybeans of only the first 4 colors, and not any of the 5th. If you pull 401, you're guaranteed to get at least one of each color.
You misunderstood the question.
How many jelly beans do you have to draw blindly to get at least 5 of one color (not 5 of ALL colors).
Obviously, after drawing 20, you will have (worst case) 4 of each color.
So 20+1 will guarantee the 5th bean that will give you 5 of one color.
Most likely, you will have hit 5 of one color before drawing 20.
-t
|
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Dec 1999
Status:
Offline
|
|
Oops, I misread it. I thought it was 1 of each color.
|
"…I contend that we are both atheists. I just believe in one fewer god than
you do. When you understand why you dismiss all the other possible gods,
you will understand why I dismiss yours." - Stephen F. Roberts
|
|
|
|
|
|
|
|
Mac Elite
Join Date: Jun 2000
Location: Boston, MA
Status:
Offline
|
|
|
Emergency Medicine & Urgent Care.
|
|
|
|
|
|
|
|
Moderator Emeritus
Join Date: Mar 2004
Location: Copenhagen
Status:
Offline
|
|
Originally Posted by Snow-i
So how many would you need to pull out to make sure that you are guaranteed 5 of a single color left in the jar?
None. They are all already in the jar
Well, that’s a bit too easy: one.
Edit: Actually, no, it’s not too easy, ’cause it doesn’t say whether or not you have to pull any out at all; so the answer could be zero, too.
Double-edit: Oh. White text. Meh.
(
Last edited by Oisín; Nov 2, 2010 at 07:39 PM.
)
|
|
|
|
|
|
|
|
|
Mac Elite
Join Date: Jun 2001
Location: Chicago
Status:
Offline
|
|
Hm. When I read the question, I thought it to mean the number that would guarantee 5 of a particular color. In which case I think the answer is 405 (as others have pointed out, although improbable, you could pull all of the other 4 colors before you pull any of your particular color).
But yeah - it seems everyone else has ready it to guarantee 5 of any color. Big difference. And when in doubt, 42 always works!
|
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Dec 2000
Location: Caught in a web of deceit.
Status:
Offline
|
|
Heh. I was thinking 405 too. Misread the question I guess. It seems the biggest brain teaser here is just reading the question right.
Originally Posted by turtle777
Possible != guaranteed.
Option = on a Mac. ≠
|
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Jun 2001
Location: planning a comeback !
Status:
Offline
|
|
Originally Posted by Eug
Option = on a Mac. ≠
I'm on my iPad.
-t
|
|
|
|
|
|
|
|
|
Professional Poster
Join Date: Dec 2000
Location: Chicago, Illinois
Status:
Offline
|
|
This is an application of the Pigeonhole Principle.
Assume the colors are red, blue, green, yellow, and orange).
In the worst case, if you take out 20, then you can have 4 reds, 4 blues, 4 greens, 4 yellows, and 4 oranges (so no 5 of a kind). But on the next choice, you will end up with a 5th color in any category.
Therefore, the answer is 21 (like others have explained above).
|
|
|
|
|
|
|
|
|
Games Meister
Join Date: Aug 2009
Location: Eternity
Status:
Offline
|
|
Math makes me drink. To do that legally, you have to be 21.
So therefore, the answer is 21.
|
|
|
|
|
|
|
|
|
Posting Junkie
Join Date: Apr 2007
Location: Iowa, how long can this be? Does it really ruin the left column spacing?
Status:
Offline
|
|
|
|
|
|
|
|
|
|
|
Moderator Emeritus
Join Date: Mar 2004
Location: Copenhagen
Status:
Offline
|
|
Originally Posted by The Final Dakar
Math makes me drink. To do that legally, you have to be 21.
So therefore, the answer is 21.
This solution makes my head hurt.
So for you, the answer is 21; for me, the answer is 15 (for low-percentage beverages) or 18 (for high-percentage beverages); and for a practicing Muslim, the answer is never/infinity?
That’s the toughest brain teaser ever.
|
|
|
|
|
|
|
|
|
Professional Poster
Join Date: Mar 2002
Status:
Offline
|
|
I'm thinking 405
Oops, I read it as 5 of each color, but now I realize that it reads one of each color, so I change my answer to 401.
I guess I read it wrong again. Five of a single color? hmmm. My answer would then be . . . I think 21. I'll have to think about it for a minute.
|
|
|
|
|
|
|
|
|
Registered User
Join Date: Apr 2001
Location: The Intertube
Status:
Offline
|
|
(
Last edited by Sealobo; Nov 3, 2010 at 04:38 AM.
Reason: wrong answer.)
|
|
|
|
|
|
|
|
|
Registered User
Join Date: Apr 2001
Location: The Intertube
Status:
Offline
|
|
"guaranteed" is the keyword.
|
|
|
|
|
|
|
|
|
Registered User
Join Date: Apr 2001
Location: The Intertube
Status:
Offline
|
|
assume ALL the color REALLY hates your guts and it just wouldn't let you draw 5 unless all other possible options are exhausted.
so it's 21
(
Last edited by Sealobo; Nov 3, 2010 at 04:39 AM.
)
|
|
|
|
|
|
|
|
|
Addicted to MacNN
Join Date: Feb 2001
Location: Your Anus
Status:
Offline
|
|
|
My sig is 1 pixel too big.
|
|
|
|
|
|
|
|
Clinically Insane
Join Date: Nov 1999
Location: 888500128, C3, 2nd soft.
Status:
Offline
|
|
Five, if you're Chuck Norris.
|
|
|
|
|
|
|
|
|
Moderator
Join Date: Jun 2000
Location: inside 128, north of 90
Status:
Offline
|
|
Chuck Norris and I agree then.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Forum Rules
|
|
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
|
HTML code is Off
|
|
|
|
|
|
|
|
|
|
|
|