Question

Ritchie wants to paint his bedroom ceiling and four walls.Both the ceiling and walls are 8 feet by 8 feet.A gallon of paint covers 40 squares feet.Which expression can be used to find the # of gallons of paint Ritchie needs to buy?

Answer 1

$\textrm{Number of gallons of paint required = }\frac{\textrm{Total Area Covered}}{\textrm{Area covered per gallon}}$

Step-by-step explanation:

   Each gallon of paint covers $40$ $sq\textrm{ }ft$ . All sides of the room as well as the wall are of $8\textrm{ }ft\textrm{ }$×$8\textrm{ }ft$ dimensions.

   So, clearly, the total paint covers all the walls and the roof. So, we can infer that $\textrm{Total Area covered}=\textrm{ (Number of gallons of paint used) x}\textrm{ (Area covered per gallon)}$

$\textrm{Total Area covered = (4walls + 1 ceiling)\textrm{x}(Area of each wall)}$

$\textrm{Total Area covered = }8\textrm{ x }5\textrm{ x }5\textrm{ sq ft}$$\textrm{ = }320\textrm{ sq ft }$

$\textrm{Number of gallons of paint required = }\frac{\textrm{Total Area Covered}}{\textrm{Area covered per gallon}}$$\textrm{ = }\frac{320\textrm{ sq ft}}{40\frac{sq ft}{gallon}}\textrm{ = }8\textrm{ gallons}$

∴ Number of gallons of paint required = $8\textrm{ gallons}$