Please help will brain list too.

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?

With both problems. a.s.a.p directions on photo ^

Asix-sided number cube is rolled twice. what is the probability that the first roll is an even numbe and the second roll is a number greater than 4?