Ged ready mathematical reasoning test questions papers

(40 points) i need some . an answer definition is appreciated as well.

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much

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?