So Ms. Jarvik (nee Savant) thought it was one of them thar woodchucky tongue twisters.http://www.straightdope.com/classics/a3_187.html
Which might almost pass the “red face” test if there were anything at all tongue twisty about “If a hen and a half…”
Whadda maroon!
Not to appear to be too persnickety, but . . . the answer is two. You cannot have 1 1/2 chickens, you must have 1, 2, 3, etc. Thus, if one chicken will not be able to produce 6 eggs in 6 days, but the equivalent of 1 1/2 would, then you would need two chickens.
Couldn’t the question be averaging the production of - say - 3 chickens?
You can’t have 1 1/2 eggs, either. But you can still divide the number of hens and eggs you do have to reach some answer in terms of fractional hens and fractional eggs. It’s like my agreeing to pay you one-third of a dollar per hour: there is no currency unit equal to one-third of a dollar, but we can still find out how much I owe you by dividing your hours worked by three.
Cecil quotes Marilyn as finally saying it was a logic problem, but that ignores the premise. If you are in a place where a half-chicken can lay a half-egg, you must be in a parallel universe where our familiar laws of physics and logic do not apply. The answer might be one hen or two-thirds of a hen, but it could also be eighteen skinks or a manual typewriter.
The parallel universe factor is better expressed in the version of the puzzle I learned. "If a chicken-and-a-half can lay an egg-and-a-half in a day-and-a-half, how many pizzas does it take to go around a dog house?" There are many answers to that one. For example, “spanners, darkly.” 
Really? It happens all the time in the world I live in. The left half of the chicken lays the left half of the egg, and the right half of the chicken lays the right half of the egg. Just because the halves are firmly attached to each other, doesn’t mean they aren’t there.
This kind of math would be very useful for someone who had a great many chickens. A large poultry operation might have thousands of chickens, but the proprietor might notice that for every 1.5 chickens he has, he gets an output of 1.5 eggs per 1.5 days. Therefore, for every 1.5 chickens he has, he gets an output of 6 eggs per 6 days.
In most businesses that deal in large volumes of product they typically calculate cost down to fractions of a penny. Of course, fractions of a penny don’t exist, but 2 pieces of gum cost 5 cents they are valued at 2.5 cents each, right? Calculate that cost over billions of pieces of gum and it adds up dramatically. Essentially it’s no different than the census bureau stating that each family, on average, has 2.4 kids or some such number.
Regardless, it’s a thought question that has no bearing on reality. It’s a straight theoretical word problem, and not a difficult one at that.
Have you heard the one about the dairy farmer who wants to increase milk production, and asks for proposals from an engineer, a psychologist, and a mathematician?
The engineer studies the problem, and says, “Okay, you need to maximize the ratio of dairy-producing cows to available space,” and produces a complex diagram showing a building that is supposed to accomplish this.
The psychologist studies the problem, and says, “Happier cows produce more milk,” and produces a mockup of a farm environment that is supposed to optimize each cow’s individual output.
The mathematician studies the problem, and says, “First, assume the cow is a sphere.”
I’m almost too embarrassed to say that while I eventually saw the light in the “plane on a conveyor belt” thread but this one still has me stumped mathematically. And maths are usually where I do ok on multiple subject tests :o
Wow, that was 16 years ago !!! I remember that puzzle quite well because I wrote to her almost immediately and told her she was wrong (with an appropriate explanation). I suspect that a lot of people wrote to her too. 
Do you like that half-hearted, really-don’t-mean-it, “admission” of her mistake? :rolleyes:
Conversely, remember when she (in a later column) answered that probability problem (based on the “Let’s Make A Deal” Door number one, etc?) She was correct but I don’t know how many times she would reprise that puzzle whenever someone else would say she was wrong. It was practically a regular feature of her column for a while. What a phony.
The mathematician says “First, assume the cow is a sphere of uniform density.”
Jeez, some people just can’t tell a joke 
I believe the canonical version is, “Consider a spherical cow…”
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This is a common logic problem often expressed in other manners (x number of painters to paint x number houses in x days) The nugget of the intuitive trap is that when you multiply by 2/3 (to turn 1-1/2 to 1) you cannot divide the days.
Based on the puzzle 27.8739 chickens could lay 27.8739 eggs in 1-1/2 days. The time still remains constant. Once you untrain your mind to spot a pattern where none really exists, the problem is trivial. In fact, I’d say it really is much easier to grasp the concept once you think about it than the Monty Hall problem or especially the plane on the conveyor belt.
I’ve heard a slightly different version of this classic riddle - to wit;
If a hen and a half can lay an egg and a half in a day and a half, how long does it take a grasshopper with a wooden leg to kick all the seeds out of a dill pickle?
Answer: “Door #3” or “Fish”, depending of course on how much wood the woodchuck chucked that morning.
When I heard it, the grasshopper had a hook on his foot.
I’m in full agreement. Sure, you’ll end up with 8 eggs but you’ll have met the requirement of six eggs in a realistic fashion with the minimal number of chckens.
The question does not set a limit. If it is important to you, you can destroy two eggs.
There is no way that you’ll get 2 eggs in six days from half a chicken. If you don’t believe me ask any chicken farmer or veterinarian.
I hope Cecil responds to this challenge.
Imagine that. Brianron and I outsmarting Marilyn vos Savant and Cecil Adams
It’s be nice if you read some of the earlier posts, or even read the column by Cecil before commenting? As Johnny LA pointed out, Cecil did say:
And, as several people have noticed, if you’re not happy with 1.5 chickens, this that this is really an abbreviation for 1.5 thousand chickens, you OK with that? I hear people talking that way about money all the time, saying “two” and meaning $200.
Very carefully
So what. Cecil is not the final arbiter of someone elses question
No. You just added information to fit Cecil’s solution . We are not looking for 6000 eggs. If that extention to thousands is legitimate, all we have here is a boring third grade math question. The mistake you are making is not reading the question carefully. Remember how your math teacher told you to read the question carefully?
One hen won’t get you the six eggs you need by Saturday, but two hens can.
Just to add, the hen question is very similar to the ladder question where a person climbs three rungs and drops by two rungs each day. Cecil’s style of logic would just assume that the climber achieves one rung per day and will require ten day to climb a ten rung ladder. Sheesh.