This is a well-known local puzzle.
An old farmer has 17 cows and three sons. After his death, this is what the will contains: "I have decided that the livestock will be distributed among the three sons like so: A, the oldest, will get half of all cows. B, the middle son, will get a third of all. C, the youngest, will get a ninth.
No cow is to be harmed, or partly owned; otherwise no one gets any, and the cows are to be given away to the village."
How do the sons resolve this puzzle?