The net profit for four months of T. N.T Corporation is given in the table below. January: $16,800, February: 4,500, March: 39,900, April: 12,000. What was the net profit for the four month period?

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?