In this question most of the information's required are already given. The only important thing to know for solving this question is the conversion between U.S. quart and liter.
We already know
1 U.S. quart = 0.946 liter
Then
6 U.S. quart = 0.946 * 6 liter
= 5.676 liter
= 5.68 liter
So the container in question can hold 5.68 liter.
