A room has one door, two windows, and a built-in bookshelf and it needs to be painted. Suppose that one gallon of paint can paint 120 square feet. The length and width of the door is 9ft by 3.5ft. The length and width of the windows are 4ft by 3ft. The length and width of the book shelf is 9ft by 4 ft. The length, width, and height of the room is 20ft by 25ft by 20ft. Calculate and output the amount of paint needed to paint the walls of the room.
The area of the sides = [2length + 2width]* height = [ 2 * 20 + 2 * 25 ] * 20 = [ 40 + 50] * 20 = 90 * 20 =
1800ft^2 (1)
Area of door = 9 *3.5 = 31.5 ft^2 (2)
Area of windows = 2 * 4 * 3 = 24 ft^2 (3)
Area of bookshelf = 9 * 4 = 36 ft^2 (4)
So....(assunimg that the bookshelf isn't painted ).....the area to be painted is
(1) - (2) - (3) - (4) =
1800 - 31.5 - 24 - 36 = 1708.5 ft^2
So....the number of cans of paint needed is 1708.5 / 120 = 14.2 [ round to 15 cans ]
