From: adams@bellini.berkeley.edu (Adam L. Schwartz)
Subject: Re: Seventh Century A.D. Armenian Math Problems
Nntp-Posting-Host: bellini.berkeley.edu
Organization: U.C. Berkeley -- ERL
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In article <1r6qn1INNd0n@flop.ENGR.ORST.EDU> koc@rize.ECE.ORST.EDU (Cetin Kaya Koc) writes:
>> Problem 1
>> 
>> My father told me the following story. During the famous wars between the 
>> Armenians and the Persians, prince Zaurak Kamsarakan performed extraordinary 
>> heroic deeds. Three times in a single month he attacked the Persian troops. 
>> The first time, he struck down half of the Persian army. The second time, 
>> pursuing the Persians, he slaughtered one fourth of the soldiers. The third 
>> time, he destroyed one eleventh of the Persian army. The Persians who were 
>> still alive, numbering two hundred eighty, fled to Nakhichevan. And so, from 
>> this remainder, find how many Persian soldiers there were before the  
>massacre.
>> 
>
>Answer: a(1-1/2-1/4-1/11)=280 -> a = 1760
>

I thought the implication was that the prince destroyed one fourth of the
remaining Persian troops on the second round, and then 1/11 of those remaining
on the third round.  This would mean

Answer: a*(1 - 1/2)*(1 - 1/4)*(1 - 1/11) = 280  -->  a = 821.333


