What is a prime number

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?

If private savings 'v' = 0.75s and total savings 's' equals $4.20 billion, solve for public and private savings.

Find the missing factor. write your answer inexponential form.9^2=9^4×