It says that the amount of lemonade is equally spread among six glasses, right?
So, you just have to take the total amount of lemonade (2/3 quart) and divide it by how many glasses you need to fill (6).
2/3 divided by 6 = 0.11111111111111111111111111111111111111111111111 quarts.
Your final answer is that each cup will be filled with 0.1 (repeating) quarts of lemonade. In fractional form, you could say that each cup will be filled with 1/9 quarts of lemonade.
