SOLUTION: In a certain party each one of the group drinks coke or beer or whiskey or all. also 400 drink coke, 500 drink beer and 300 drink whiskey. 100 drink coke and beer, 200 drink beer a

 

 
There are 7 regions in the Venn diagram above
Circle C contains all the Coke drinkers, which are of 4 types:
Circle C is made up of 4 regions d,e,f, and h
Those in region d drink Coke but do not drink beer or whiskey
Those in region e drink Coke and beer, but do not drink whiskey.
Those in region h drink Coke, beer, and whiskey.
Those in region g drink Coke and whiskey, but do not drink beer.
 
Circle B contains all the beer drinkers, which are of 4 types:
Circle B is made up of 4 regions e,f,h, and i
Those in region e drink beer and Coke, but do not drink whiskey.
Those in region f drink beer, but do not drink coke or whiskey.
Those in region h drink beer, Coke, and whiskey.
Those in region i drink beer and whiskey, but do not drink Coke.
 
Circle W contains all the whiskey drinkers, which are of 4 types:
Circle W is made up of 4 regions g,h,i, and j
Those in region g drink whishey and Coke, but do not drink beer.
Those in region h drink whiskey, Coke, and beer.
Those in region i drink whiskey and beer, but do not drink Coke.
Those in region j drink whiskey, but do not drink Coke or beer.
 
Let's start with this clue:

>>...1 who drinks whiskey does not drink Coke. how many are in the group?

I take this to mean nobody drinks both Coke and whiskey.  That
means there are nobody in regions g and h.  So we put 0's there







>>...100 drink coke and beer...<<
 
So all 100 go in e since there are 0 in the middle. So we replace
e by 100



>>...200 drink beer and whiskey...<<

So all 200 go in i since there are 0 in the middle. So we replace
i by 200



>>...400 drink coke...<<

Three of the regions of circle C have 100, 0 and 0 in them.
So we have already accounted for 100 of the Coke-drinkers,
so the remaining 300 coke-drinkers are in region d.  So we
replace d by 300:



>>...500 drink beer...<<

Three of the regions of circle B have 100, 0 and 200 in them.
So we have already accounted for 300 of the beer-drinkers,
so the remaining 200 beer-drinkers are in region f.  So we
replace f by 200:


 
>>...300 drink whiskey...<<

Three of the regions of circle W have 0, 0 and 200 in them.
So we have already accounted for 200 of the whiskey-drinkers,
so the remaining 100 whiskey-drinkers are in region j.  So we
replace j by 100:



Now we have all 7 regions filled with numbers, so
we add them up:

300+100+200+0+0+200+100 = 900

So there were 900 at the party.  What a party!

Edwin