Consider first,1/2+1/3+1/9 =17/18. The molecule is 17, corresponding to 17, and the denominator is 18, corresponding to 18. Therefore, there are:

Borrowed horses have 18 horses.

Dard: 18× 1/2=9.

Laoerde: 18× 1/3=6.

Third: 18× 1/9=2

* * * Score: 9+6+2= 17.

Remaining: 18- 17= 1, returned.