B. The total area painted is 864; they must buy two cans of paint.
Step-by-step explanation:
Step 1:
A rectangle's area can be calculated by multiplying its length and its width. The wall is made up of 5 different types of rectangular walls. All walls are 8 feet tall but the length varies.
Step 2:
The area of the 20 feet long wall =
The area of the 10 feet long wall =
The area of the 5 feet long wall =
The area of the 4 feet long wall =
The area of the 15 feet long wall =
The area of all the walls = 432 square feet.
Since there are two sides for every wall, total area = square feet.
Step 3:
If one paint can covers 500 square feet,
the number of cans required to paint 864 square feet = cans.
so 2 paint cans are needed to paint 864 square feet which is option B.