One serving of oatmeal has 7 grams of fiber, which is 33% of recommended amount.
Let the recommended amount be y
The statement can be interpreted as
7 = 33% of y
7 = 0.33y
Divide both sides by 0.33
7/0.33 = y
y = 21.2121
Hence, the total recommended amount of fiber is $21.21 grams