Peter wants to put 2 coats of paint on both the inside and outside of the walls. There are 5 walls, each side having 45 ft2 of paintable surface. A gallon of paint covers x ft2. Explain how to write an expression to represent the number of gallons of paint Peter needs.
Both sides of one wall would be 90 square feet. Two coats of paint for both sides would be 180 square feet. There are 5 walls, so the total square feet to be painted is 5(180) = 900. So, Peter needs 900/x gallons of paint.
