The capacity of glass X is 80 percent of the capacity of glass Y. Further, ... ...

The capacity of glass X is 80 percent of the capacity of glass Y. Further, glass X contains 6 ounces of punch and is half-full, while glass Y is full. Glass Y contains how many more ounces of punch than glass X?
(A)    1
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Math - Problem Set X: Word Problems