89 A room is 7'6 wide by 9'0 long with a ceiling height of 8'0. One gallon of flat paint will cover approximately 400 square fee of wall. The number of gallons of this paint required to paint the wall?

Ignoring any allowance for doors and Windows then the wall area of this square room is : 4 x 20 x 12 = 960 sq feet.

As three coats are being applied then the total area = 3 x 960 = 2880 sq ft.

1 gallon of paint covers 465 sq ft therefore 2880 sq ft requires 2880/465 = 6.1935 gallons.

1 gallon of paint costs $20. Assume the paint is sold in 1 gallon tins then 7 tins will be required at a cost of 7 x 20 = $140.

NOTE : If the ceiling is also being painted then this has an area of 20 x 20 = 400 sq ft.

Wall + Ceiling area = 960 + 400 = 1360 sq ft. Paint area = 3 x 1360 = 4080 sq ft.

Paint required = 4080/465 = 8.7742 gallons. Therefore 9 tins costing $180.