A farmer passes on, leaving his herd of 11 dairy cows to his three sons.  
His will says:

The oldest   son gets 1/2 of the herd.
The second   son gets 1/4 of the herd.
The youngest son gets 1/6 of the herd.

The sons mourn the passing of their father, but they're pleased that each 
of them will have a (small) herd of cows... until they realize that 11 
can't be divided by 2, 4, or 6.  Following the will would result in 
cutting up cows into halves, fourths, or even sixths.  Ick!

Just then a wandering mathematician rides up on a cow.  The brothers tell 
her about their problem, and she says, "Never fear -- I can help!"  She 
dismounts, and gives her cow to the brothers, so that they have a total of 
11 + 1 = 12 cows.  Then they divide the cows according to the will:

The oldest   son gets 1/2 of 12, or 6 cows.
The second   son gets 1/4 of 12, or 3 cows.
The youngest son gets 1/6 of 12, or 2 cows.

But wait -- 6 + 3 + 2 = 11, so the three sons together have 11 cows total.  
This leaves one cow left over.  So the mathematician takes her original 
cow and rides off into the sunset, leaving the brothers stunned at the 
brilliance of her solution.

So here's the question: did each brother get a fair share, or did somebody 
get ripped off?  I'll give a couple of extra points on the next quiz to 
people who write down a reasonable answer and explanation, and give it to 
me in class on Wednesday, March 12th.