9) [5 marks] Walmart has been selling 400 refurbished 8-inch Samsung Galaxy Tablets per week at $200 each. A market survey indicates that for each 50 cents rebate offered to buyers, the number of tablets sold will increase by 60 per week. (Do NOT round your answers) a) How large of a rebate should the manufacturer offer the buyers in order to maximize revenue? What is the maximum revenue? b) If the weekly cost to produce each tablet is $10, and there is a $80,000 fixed cost per week, then what size of rebate will maximize the profit