How is the right of the mortgagee calculated if the slave and her child are sold together?

Primary text

When both the slave and her child are sold together against the debt, the right of the mortgagee attaches to that sale proportional to the value of the female slave from the total sale price. For instance, if the slave's value is one hundred, and the child's value is fifty, the slave's share constitutes two-thirds of the sale price.