The Arabian Horse  

Sadly the old man grew ill and lay dying in bed. He called his three sons to him and said, "My sons, I love you all, with all my heart, but you are not of equal age and thus I cannot share my horses amongst you evenly. To  my eldest son, I leave one half of my horses, to my second son, I leave one third of my horses, and to my youngest  son, I leave one ninth of my horses...."

With the last word, the old man closed his eyes and died.  His sons were beside themselves with grief and to add to this, they could not think of harming the horses. The  eldest spoke first, "How can we split the horses up as our father has
requested without killing some of them and dissecting their carcasses?"

At last they sought the advice of their father's oldest friend, an Arab well-known for his wise words. He thought for a few seconds and then gave the sons the answer. Each son took his share of the horses and went home happily. How did they do this?

Answer               

The wise old man lent the brothers one of his horses. Now there were 18 horses. Half of 18 is 9, so the eldest son got 9 horses, a third of 18 is 6, so the second son got 6 horses and
a ninth of 18 is 2, so the youngest son got 2 horses.
                            9 + 6 + 2 = 17
so the wise old man took his own horse home!