Answer:
1/3 of a quart of milk.
Explanation:
We have been given that Hannah has 2/3 of a quart of milk.
Now, she used half of this milk in breakfast.
Thus, in order to find the amount of milk she used we can take half of the amount of milk she initially had.
Mathematically, we have
Milk she used = 1/2 × initial amount of milk
Therefore,
Milk she used = 1/2 × 2/3
Milk she used = 1/3
Therefore, she used 1/3 of a quart of milk.