Inheritance, the Wisdom Test

Today Briquinex requires your help to solve a family matter. A peasant after he died, left as inheritance 17 horses to his 3 sons. The first was to receive 1/2 of the horses, the second 1/3 and the third 1/9 of the horses. Briquinex ask you to help the three sons to divide the inheritance without cutting any of the horses and determine how many horses should receive each of them?

photo source : wikipedia