Problem solving 7. each pair of tennis shoes costs $25. if andrea has four $5-bills, does she have enough money to buy one pair? write a number sentence. then solve.

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?