Braingle: 'Mixed up Addresses' Brain Teaser

Mixed up Addresses

Probability puzzles require you to weigh all the possibilities and pick the most likely outcome.

Puzzle ID:	#2895
Fun:	(2.48)
Difficulty:	(1.71)
Category:	Probability
Submitted By:	204_BLaZe_41

Duke Maverick worked for a packaging company. One day, Duke received four separate orders and accidentally mixed up the addresses, so he applied the address labels at random. What is the probability that exactly three packages were correctly labelled?

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Comments

rohddawg Mar 30, 2002	umm... ok... but then what is the probability of that... since u were asking for one?
mad-ade Mar 31, 2002	it is not impossible, you answer that in your answer. For 3 to be correct, obviously all four need to be correct, and what is the possablity of that. so therefore it is not Zero, because no matter how slight the chance of getting all four correct (to allow the three in question to be correct) it is not Zero as stated. blaze strikes again (and misses)
tell-UN-igent Apr 01, 2002	You are too funny mad-ade.
cathalmccabe Apr 03, 2002	1/24 I think, but I'm not sure
cathalmccabe Apr 03, 2002	By the way, if you are trying to TRICK people, thats clever, trick them by putting it in Probability rather than TRICK!
chamber44 May 18, 2002	Cath, he DID put it in probability. And about your dogs puzzle...when did they become bears? (look at one of your comments on that one.)
Andy1608 May 21, 2002	Blaze is right Mad-ade, the question asks what's the probability of EXACTLY 3 being correctly labelled. If all 4 are, that's not exactly 3 is it?
madman44 Jun 24, 2002	Exactly 3 are there labeled correctly- and so is the fourth for that matter. Mad Ade is correct.
cathalmccabe Jul 29, 2002	I was just looking at this again and see my guess of 1/24 is wrong.I spent a bit longer thinking about it, is the answer 1/6? If you take the first one and its definitely wrong, you have 1/3 in getting it in the right place. Then the second one only has 1/2 and the other two have to be swaped so they are certainties if you get the first two right?
snaps Nov 07, 2002	I'm with madman, andy and blaze on this. The question asks for the probability of "exactly three" being correct. If three are correct then so is the fourth meaning that there can never be "exactly three" that are correct, there are more than three correct. The wording of this question is important, which seems to have been overlooked by some people.
jimbo Mar 14, 2003	I liked the puzzle Blaze and I speak English so I know what "Exactly 3" means.
mr_brainiac Jan 04, 2006	none, zip, nuttin, zee-row, NADA, as in "nada chance"
YVAU Mar 02, 2006	Good one. It does say "exactly 3", not at least 3.
brainjuice Mar 31, 2006	the probability is not ZERO so your answer is wrong. but i like your puzzle, i really didnt realize that 3 the same then the fourth also must be the same.. good teaser
dishu Apr 26, 2006	the answer is right as it asks for "EXACTLY 3" being correct which is not possible. Because if there are 3 correct,then so is the 4th one making it MORE THAN 3 CORRECT rather than EXACTLY 3 CORRECT
Dedrik Aug 29, 2006	Math Vocab for the win
xdbtcp Sep 24, 2010	Well, if a packaging company hires a guy who is happy to put on labels randomly, there's a pretty good chance that one of the address labels was written incorrectly, so....it is possible that there will be exactly 3 correct.