Answer:
The answer to your question is: 1.78 gallons
Step-by-step explanation:
Data
1 gallon = 400 ft²
room = 8 ft x 20 ft x 7 ft
Process find the area of the 6 walls of the room
Area of the floor and ceiling
A = base x width
A = 20 x 8
A = 160 ft² x 2
A = 320 ft²
Area of the walls
Area = base x width
Area = 2(20 x 7) + 2(7 x 8)
Area = 280 + 112
Area = 392 ft²
Total area = 320 + 392 = 712 ft²
1 gallon ------------------- 400 ft²
x ------------------- 712 ft²
x = (712 x 1)/400
x = 1.78 gallons
I consider that Maria will paint both the floor and the ceiling