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?

What percentage of the general u. s. population are high-school dropouts? the statistical abstract of the united states, 120th edition, gives the percentage of high-school dropouts by state. for convenience, the data are sorted in increasing order.