John's room is shaped like a box. It has a flat ceiling that is a rectangle that is 14 feet long and 8 feet wide and the walls are 7 feet high. It has one door that is 6 feet high and 3 feet wide. It has two windows that are each 3 feet high and 30 inches wide. John wants to paint the walls and ceiling, but not the door or windows. He can paint 100 square feet with a quart of paint and paint costs $3.50 per quart. He has to buy whole quarts and may have some paint left over. It will cost John to paint his room.

We have to calculate the whole area (in square feet) that John would have to paint. This area would include the area covered by the ceiling and walls, and exclude the area covered by the door and two windows:

1. Area covered by the ceiling = 14 × 8 = 112 square feet

2. Area covered by walls = perimeter of ceiling × height of wall = 2 × (14 + 8) × 7 = 308 square feet

3. Area covered by the door and two windows = (6 × 3) + (3 × 2.5 × 2) = 33 square feet

(Note: width of window = 30 inches = 2.5 feet)

Therefore, the area that would need to be painted = 112 + 308 — 33 = 387 square feet.

If John can use one quart to paint 100 square feet at $3.50, then he would need 3.87 quarts to paint 387 square feet; however, since he has to buy whole quarts, he would need 4 quarts instead of 3.87, and this would cost = 4 × 3.50 = $14