To find the number of black horses in the herd, we first need to subtract the number of white horses from the total number of horses.
Given:
- Total horses = 88
- White horses = 31
The number of black horses can be calculated as follows:
\[ \text{Number of black horses} = \text{Total horses} - \text{White horses} = 88 - 31 = 57 \]
Now, we want to find the ratio of black horses to all horses. The ratio can be represented as:
\[ \text{Ratio of black horses to all horses} = \frac{\text{Number of black horses}}{\text{Total horses}} = \frac{57}{88} \]
Therefore, the number of black horses in the herd is 57, and the ratio of black horses to all horses is \(\frac{57}{88}\).