Room paint usage

How many kg of paint will we use to paint the walls and ceiling of a room with a length of 9 m, a width of 6 m, and a height of 3.2 m if 1kg of paint is enough for approximately 6 m²? Subtract 6 square meters from the surface of the walls, which are the doors and windows.

Final Answer:

m =  24 kg

Step-by-step explanation:

$$\begin{gathered} a=9\text{m} \\ b=6\text{m} \\ c=3.2\text{m} \\ {S}_1=6{\text{m}}^2 \\ {S}_2=a\cdot b+2\cdot c\cdot (a+b)=9\cdot 6+2\cdot 3.2\cdot (9+6)=150{\text{m}}^2 \\ S=S_2-S_1=150-6=144{\text{m}}^2 \\ \rho =1/6=\frac{1}{6}\doteq 0.1667{\text{kg/m}}^2 \\ m=\rho \cdot S=0.1667\cdot 144=24\text{kg} \end{gathered}$$

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