Please answer both

(R R N 19. An open box is to be made from a 3 ft by 8 ft rectangular piece of sheet metal by cutting out squares of equal size from the four corners and bending up the sides. Find the maximum volume that the box can have. 20. A chemical manufacturer sells sulfuric acid in bulk at a price of $100 per unit. If the daily total production cost in dollars for x units is C(x) =100.000+ 50x + 0.0025x* and the daily production capacity is at most 7000 units, how many units of sulfuric acid should be manufactured and sold daily to maximize the profit? Would it benefit the manufacturer to expand the daily production capacity