From the given diagram, we get that the surface area of the walls of the rectangular room (without the 5m² for the door and windows) is:
[tex]\text{Area}=2(4.8m+6.8m)\cdot2.6m-5m^2\text{.}[/tex]
Simplifying the above result we get:
[tex]\begin{gathered} \text{Area}=2(11.6m)\cdot2.6m-5m^2 \\ =60.32m^2-5m^2 \\ =55.32m^2\text{.} \end{gathered}[/tex]
Since one liter of paint covers 9.5m², then Shelby needs:
[tex]\frac{55.32}{9.5}\approx5.82[/tex]
liters of paint.
Therefore, the least amount of paint that Shelby must buy to paint the room is 6 liters.
Now, notice that:
[tex]6=4+1+1.[/tex]
Then Shelby can buy a can of 4L of paint and 2 cans of 1L of paint. Using the given table we get that the paint cost:
[tex]24.95+7.99+7.99=40.93[/tex]
dollars.
Answer:
(a) 6 liters.
(b) $40.93.
