Answer:
It depends on how many goats the farmer has in the first place.
Explanation:
If he has 0 goats he needs 10 more.
If he has 1 goat he needs 9 more.
If he has 2 goats he needs 8 more.
If he has 3 goats he needs 7 more.
If he has 4 goats he needs 6 more.
If he has 5 goats he needs 5 more.
If he has 6 goats he needs 4 more.
If he has 7 goats he needs 3 more.
If he has 8 goats he needs 2 more.
If he has 9 goats he needs 1 more.
If he has 10 goats he needs 0 more.