Answer: There are 30 goats in the farm.

Solution:

1. Add the numbers in the ratio

  4 + 3 + 2 + 1 = 10

2. Divide 100 and the sum of the numbers in the ratio

   100 ÷ 10 = 10

3. Multiply the quotient to each number in the ratio

   4 × 10 = 40 (number of chickens)

   3 × 10 = 30 (number of goats, ANSWER)

   2 × 10 = 20 (number of cows)

    1 × 10 = 10  (number of carabaos)