The marketing department at Gadgets Galore has found that when certain iPods are sold at a price of p dollars per unit, the revenue R (in dollars) as a function of the price p can be demonstrated by the function given in the graph below. s00000 700000- 600000+ 500000+ 400000- 300000+ 200000+ 100000- + 100 20 40 60 80 120 140 160