Answer
16 cups
Step-by-step explanation
First we find the difference between 1/8 and 3/4 of the container.
3/4 - 1/8 = 6/8 - 1/8
 = 5/8
From here we can say that;
5/8 full of water represent 10 cups, what of 8/8 full of water?
5/8 ⇒ 10 cups.
8/8 ⇒ ?
Using cross multiplication;
(8/8 × 10) ÷ 5/8 = 10 ×8/5
 = (10 × 8)/5
 = 80/5
 = 16 cups