Middle school math pls explain answer

What is the measure of ac? 5 units 13 units 26 units 39 units

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

Calculate the missing value. round the answer to on decimal place. start with 70, increase it by 21%, and end up with