16. The ground area of a piece of land of a supermarket used for parking cars is 25(x² - 8x + 16) square metres.
(i) If the area of a parking lot for a vehicle is (x-4)² square metres, how many cars can be parked there?
(ii) If 4 units of the parking lot have been booked by the supermarket, how many parking lots are left? ​