From the question, we can derive the following?
1 1/3 cups of milk to one cup of flour.
We should find the quantity of flour that will be needed if 2 1/3 cups of milk is used.
Let x be the unknown quantity of flour use.
1 1/3 = 4/3
2 1/3 = 7/3
4/3 ---------- 1
7/3 ---------- x
Lets cross multiply:
4/3 * x = 7/3 * 1
4/3x = 7/3
Divide both sides by 4/3
x = 7/3
4/3
x = 7/3 * 3/4
The 3 cancels out:
x = 7/4
x = 1 3/4
Therefore, the quantity of flour needed for a 2 1/3 cups of milk is 1 3/4.