Kevin operates a movie theater that sells about 800 tickets per day for $8 each. kevin predicts that for each $0.50 increase in the ticket price, 40 fewer tickets will be sold. let x represent the number of $0.50 price increases and f(x) represent the total earnings from ticket sales. f(x)=-20x^2+80x+6400 kevin wants to determine the best potential earnings from ticket sales each day. complete the following statement for this situation. the function reveals that the or maximum) earnings from ticket sales will be $, 6400, 720, or 320) , four, six, or two) $0.50 price increases.