4. See the graph to the right. List the open intervals where the function is concave up and concave down. Concave up: Concave Down: 51.5) Find any inection points (just the :rvalues} of the function f (at) = 32(5):: + 24). Leave all answers exact - not rounded. _ _ _ A deli sells 720 sandwiches per day at a price of $6 each. A market surveyr shows that for ever $0.10 reduction in price, 40 more sandwiches would he sold. [a] Write a revenue equation, BLT), to represent the total revenue, where 3; represents the number of $0.10 reductions to the price of a sandwich. (b) What price per sandwich should the deli charge to get the maximum revenue? (Use calculus techniques from class and the equation you wrote in part (a).)