The graph to the right shows the total sales in thousands of dollars for a department store during a typical 24-hour period. a) Calculate the rate of sales during the period between 8 A.M. and 10 A.M. b) Which 2-hour interval in the day sees the highest rate of sales and what is the rate? 24- 20- 16- 12- 8- Sales in Thousands of Dollars 0- 2 A.M. 6 A.M. 12 noon 6 P.M. 10