In the problem it is already given that Anna had made 400 quart of lemonade. Now she poured them into smaller containers. each container had the capacity to hold 4/7 of a quart. It is required to find out the number of containers required to hold the full 400 quart of lemonade.
Then,
4/7 quart of lemonade can be filled in = 1 container
400 quart of lemonade can be filled in = [(7/4) * 400] containers
= 700 containers
So 700 containers having the capacity to hold 7/4 quart is required to hold a total of 400 quart of lemonade made.