Four people are in a bar.
Ben owes Glen a drink. Glen owes Rhen two drinks. Rhen owes Sven three drinks. Sven owes Ben four drinks.
To settle up, what is the minimum number of drinks that need to be bought by who for whom?
(In reply to
Getting Drunk by TomM)
An alternate view:
Ben owes one drink and is owed four. Net result is that Ben is owed three drinks.
By similar logic, Glen owes one drink, Rhen owes a drink, and Sven owes a drink.
If Glen, Rhen, and Sven each buy a drink and put it into a pool, and Ben takes all three drinks, then everybody is settled up.
Of course, usually by this part of the evening nobody will figure this out, and it'll all be settled by seeing who can perform a better rendition of "Louie, Louie".