A brand of cereal had 1.21.2 1.2 1, point, 2 milligrams (mg)(\text{mg}) (mg) left parenthesis, start text, m, g, end text, right parenthesis of iron per serving. Then they changed their recipe so they had 1.8 mg1.8\,\text{mg} 1.8mg 1, point, 8, start text, m, g, end text of iron per serving.

The percent increase in iron is 50 %.

Step-by-step explanation:

The percentage increase is given by

Firstly we find the increase or the difference in the amount of iron per serving as follows

Increase in iron per serving = Final iron content - Initial iron content

= 1.8 mg of iron - 1.2 mg of iron= 0.6 mg of iron

Next, we divide the increase by the initial or original iron content which is

1.2 mg of iron per serving

Hence  

Next, we multiply by 100 to get the value as a percentage,

That is 0.5 × 100 = 50 %

The percent increase in iron = 50 %.