Question 939604
Area of Walls:
2(12 ft x 8 ft)+2(20 ft x 8 ft)=A(walls)
        2(96 ft^2)+ 2(160 ft^2)=A(walls)
              192 ft^2+320 ft^2=A(walls)
                       512 ft^2=A(walls)
Area of ceiling:
                  12 ft x 20 ft=240 ft^2=A(ceiling)

Total Area: Answer A
           A(walls)+ A(ceiling)=A(total)
              512 ft^2+240 ft^2=752 ft^2
Number of Gallons: Answer B
coverage=70.87 ft^2 /gallon 
         752 ft^2/70.87 ft^/gal=gallons needed
                      10.61 gal=gallons needed
Cost of Paint: Answer C
You would need to buy 11 gallons at $22.47/gallon to have sufficient paint

                           cost=11 gallons x $22.47/gallon
                               =$247.17