[net.puzzle] pig puzzle

barry@ihuxt.UUCP (11/18/83)

you have 4 pigpens.
you have 21 pigs.
you have to place an odd number of pigs in each pigpen.
(zero is not an odd number).

(this was a homework problem for the 10 year old daughter of a guy in
our department).

				Rich Barry
				ihuxt!barry

walsh@ihuxi.UUCP (11/18/83)

You didn't say if you had to put all the pigs in pens! Put one in each
pen and have a big luau with the other seventeen! :-)

B. Walsh

barry@ihuxt.UUCP (11/19/83)

There is some confusion about this puzzle.  You must put ALL 21
pigs in their pigpens.  Cooking, Burning, Eating, and Luau's
are not allowed!!!!!

					Rich Barry
					ihuxt!barry

lied@ihlts.UUCP (11/19/83)

Okay, I'll bite.  It can't be done.  The sum of two odd numbers
has to be even --> the sum of four odd numbers has to be even-->
no way can four numbers add up to 21.

If that's not it, my second guess is that the probability is 2/3.

	Bob "I hope Martin Gardner fries in Hell" Lied
	...ihnp4!ihlts!lied

robison@eosp1.UUCP (11/20/83)

The problem is to place 21 pigs in 4 pigpens so that each
contains an odd number of pigs.  There are many solutions
provided that some pigpens are wholly contained inside other
pens.  E.g., suppose that pigpen 1 is wholly inside pigpen
2.  Then place pigs as follows:

pen 1:  1 pig
pen 2:  10 pigs within pen 2, but outside pen 1.
pen 3:   3 pigs
pen 4    7 pigs.

Note that all four pens contain an odd number of pigs, because
pen 2 contains its 10 pigs, plus the pig in pen one.

				- Keremath,  care of:
				  Robison
			          decvax!ittvax!eosp1
				  or:   allegra!eosp1

3391dms@hogpc.UUCP (11/21/83)

All of these answers about pens-within-pens are a bit far-fetched...

Here's my solution:

1.) you take 7 pigs, and place them in pen #1.
2.) Herd 5 more of the pigs into pen #2.
3.) Chase frantically after 3 pigs (it's getting harder to catch
    them now), and when you get them, put them in pen #3
4.) Slowly, methodically, lead each of the remaining pigs
    into pen #4. (Save the pregnant one for last...)

This leaves you with 7, 5, 3, and 9 (three adorable piglets
were born the instant ma was led through the gate).

Papa pig will be distributing cigars from pen #2...

:-)

D. M. Schmid
AT&T Consumer Products Laboratories
Holmdel, NJ

laura@utcsstat.UUCP (Laura Creighton) (11/23/83)

ou ought to be able to put
your pens together in such a way that you can place a  pig in the
space between the pens which is also closed.

(Another way to say this is to make sure the pens touch each other.)

Laura Creighton
utzoo!utcsstat!laura