Efficiency units (sleeping units with cooking facilities) which must be contained within a hotel or motel site, wherein not more than 40% of the number of units on the site are efficiency units: Each unit shall have a minimum living space of 10.80 square feet per 100 square feet of land, provided that there shall be not more than three units per 10,000 square feet. One additional unit shall be permitted for each additional 3,333 square feet in addition to the basic 10,000 square feet.