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From: brianu@ada-uts.UUCP
Newsgroups: net.puzzle
Subject: Re: A "logic puzzle"
Message-ID: <11900006@ada-uts.UUCP>
Date: Fri, 31-Jan-86 14:36:00 EST
Article-I.D.: ada-uts.11900006
Posted: Fri Jan 31 14:36:00 1986
Date-Received: Mon, 3-Feb-86 05:41:06 EST
References: <292@watdragon.UUCP>
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Nf-ID: #R:watdragon:-29200:ada-uts:11900006:000:1188
Nf-From: ada-uts!brianu    Jan 31 14:36:00 1986


>>        you have any children?". The other replies "Yes - three sons".
>>        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 revised problem has only one solution: 2 year old twins and a
9 year old.
Reasoning: There are 14 triplets whose sum is 13.  Their products range
from 11 (1,1,11) to 80 (4,4,5).  Presumably the second person knows his
(her) own age and should be able to deduce the correct answer.  However,
the product of 36 comes up twice (1,6,6 and 2,2,9) and is the only one
that comes up more than once.  Since the person is unable to deduce the
answer his age must be 36.  When the other says that the oldest weighs
61 pounds we eliminate 1,6,6 because there would be no "oldest".
Threefore the answer is 2,2,9.

Brian Utterback
Intermetrics Inc.
733 Concord Ave. Cambridge MA. 02138. (617) 661-1840
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