Sam is about to dive into a still pool, but some sunlight is reflected off the surface of the water into his eyes. On the figure, plot the exact point on the waters surface where the sunlight is reflected at Sam​

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?