10. A rectangle with sides parallel to the coordinate axes is inscribed in the ellipse + = 1. Find the largest area for this rectangle %3D 11. A billboard is to be made with 100m? of printed area and with margins 2m at the top and bottom and 4m on each side. Find the outside dimensions for the billboard if its total area is to be a minimum. 12. All 80 rooms in a Motel will be rented each night if the manager charges $40 or less per room. If he charges $(40+x) per room, then 2r rooms will remain vacant. If each room rented costs the manager $10 per day and each unrented room $2 per day in overhead, how much should the manager charge per room to maximize.his daily profit. 3. You are in a dune buggy in the desert 12km due south of the nearest