Answer:
5
Step-by-step explanation:
He bought 1, 12 ounce container for each of the set of berries. The blackberries needed 9 but he had 12 so you take the 9 away from the 12 and you are left with 3 you do the same with the raspberries and you are left with 2 then the strawberries are already at 12 ounces so you add up the 3 and the 2 and you get 5.