Can someone me with this & explain how to find the answer?

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?

Mama mia restaurant used 1 2 2 1 ? of their mozzarella cheese making pizza and the remaining 6 4 64 ounces making pasta. how many pounds of mozzarella cheese did mama mia start with?

Write down in words the number 65 405