Answer:
30 units.
Step-by-step explanation:
Let x be number of milk units sold.
It has been given that You begin the week with 20 units of milk. You purchase 40 units. Therefore, total units of milk will be units.
It has been given that your ending inventory for the week is 30 units, which means after selling x units from 60 units you are left with 30 units.
We can set this information in an equation as:
Therefore, you have sold 30 units.