Help me pls

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 f(x) = 2x + 8 and g(x) = x4, what is (gº)?

If a runner who runs at a constant speed of p miles per hour runs a mile in exactly p minutes what is the integer closest to the value p