Splitting horses

A mischievous Sheik dies and leaves 17 horses to his three sons. To the eldest, he leaves half his horses; to the middle son, one-third; and to the youngest, one-nineth. In consternation the brothers seek the wise man of the village for advice. The wise man adds his own horse to the group and makes the following division: 9 horses to the eldest; 6 to the middle son, 2 to the youngest. Then the wise man takes his own horse, now left over, and goes home.