How many ounces are in 21 cups?

To determine how many ounces are in 21 cups, we need to know the conversion rate between cups and ounces. There are 8 fluid ounces in 1 cup.

Therefore, 21 cups = 21 cups x 8 ounces/cup = 168 ounces.

So, there are 168 ounces in 21 cups.