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From: wet@whuxlm.UUCP (William Taylor)
Newsgroups: net.puzzle
Subject: Re: A "logic puzzle" (spoiler)
Message-ID: <900@whuxlm.UUCP>
Date: Thu, 30-Jan-86 11:34:59 EST
Article-I.D.: whuxlm.900
Posted: Thu Jan 30 11:34:59 1986
Date-Received: Sat, 1-Feb-86 01:28:44 EST
References: <292@watdragon.UUCP> <2578@pucc-h>
Distribution: net
Organization: AT&T Bell Laboratories, Whippany
Lines: 33

> The first asks "How old are they?", to which the second replies
> 
> 	"The sum of their ages is thirteen, and the product of their
> 	ages is equal to your age."
> 
> The first says, "I can't tell their ages from that."
> The second adds, "The oldest weighs 61 pounds."
> 
> The first says, "Now I know their ages."
> 
> -- 
> Dave Seaman	  					pur-ee!pucc-h!ags

The friend knows how old he is.
Since he doesn't have enough information to solve the puzzle
at first, there must be two or more sets of three numbers
which add up to 13 and when multiplied together equal the friend's
age.
In fact, there are only two sets of numbers that add up to thirteen
and when multiplied together give you the same number.
These are: (9 2 2) and (6 6 1).

But the friend does not know the ages of the kids yet.
So the dad tells him that the oldest weighs 61 pounds.

Now granted in real life, one of the six year olds is older than
the other, but in years, they are the same age. So,
with (6 2 2) there is no oldest.
Thus, the oldest is 9 and the other two are both two years old.

Buddy Taylor
AT&T Bell Labs
whlmos!wet