similar: A farmer dies...he has 3 sons, and at the reading of the will, it states that 1/2 of his horses go to his eldest son. 1/3 to his 2nd son, and 1/9 to his youngest son...

the boys look at the lawyer and say. "but Father had 17 horses. We can't do that!"

The lawyer thinks a bit and says, "I have a solution!"

How did he manage it?