There are 60 brown horses and 40 black horses and 20 spotted horses
Solution:
Given that there are 120 horses on a farm
of the horses are brown
Number of brown horses are:
Therefore, 1/2 of total number of horses are brown
of 120

of the horses are black
Number of black horses are:
Therefore, 1/3 of total number of horses are black
of 120

of the horses are spotted
Number of spotted horses:
Therefore, 1/6 of total number of horses are spotted
of 120

Thus there are 60 brown horses and 40 black horses and 20 spotted horses