Question

A food manufacturer can claim on a label that a food is a "good
source" in a nutrient if it has at least 10% of the recommended
daily amount of that nutrient.
The recommended daily amount for iron is 25 grams. What is
the minimum amount of iron that a serving of food must have
to claim on the label that it is a "good source of iron"?
grams

Answer 1

Greetings from Brasil...

25mg is recommended, but the minimum for the label would be 10% of 25mg. So just apply percentage (rule of 3)

  mg               %

  25   --------  100

   X    --------   10

100 · X = 25 · 10

100X = 250

X = 250/100

X = 2.5

So, it is enough that the product has 2.5mg of iron to be labeled as a "Good Source of Iron"